delivered the opinion of the court:
The primary issue presented in this appeal is whether a plaintiff may bring a retaliatory discharge action against the employee or agent who, on behalf of the plaintiffs former employer, discharged the plaintiff in alleged violation of public policy. We hold that the limited tort of retaliatory discharge recognized by this court in Kelsay v. Motorola, Inc., 74 Ill. 2d 172 (1978), should not be expanded to allow claims against such parties.
The plaintiff, Jack L. Buckner, filed a four-count complaint against Atlantic Plant Maintenance, Inc. *14(Atlantic), James L. O’Brien (O’Brien), Sedgwick James of Illinois, Inc. (Sedgwick), and Patrick J. Holden (Holden) in the circuit court of Cook County on February 28, 1995. The plaintiff alleged that he was periodically employed by Atlantic as a millwright at LaSalle Nuclear Power Station on and prior to October 13, 1993. The plaintiff further alleged that he suffered a work-related injury on September 23, 1993, while employed by Atlantic. Counts I and II of the complaint were directed at Atlantic and O’Brien. Count I charged that Atlantic and O’Brien terminated the plaintiff’s employment on October 23, 1993, in retaliation for the plaintiffs “intention to pursue and his pursuit of a certain workers’ compensation claim.” Count II realleged the allegations of count I and sought punitive damages from Atlantic and O’Brien. Counts III and IV were directed against Sedgwick and Holden. Count III charged that Sedgwick and Holden conspired with Atlantic and O’Brien to deny the plaintiff his workers’ compensation benefits by “falsely informing plaintiff on November 3, 1993, that he would receive no benefits because he failed to show up for light duty work at Atlantic and ‘unilaterally elected to keep yourself off the job.’ ” Count IV sought punitive damages from Sedgwick and Holden.
Atlantic filed an answer admitting that it had been the plaintiffs employer. As an affirmative defense, Atlantic alleged that it had “laid off’ the plaintiff as part of a “reduction in force.”
O’Brien filed a motion to dismiss the plaintiff’s complaint against him pursuant to section 2 — 619(a) of the Code of Civil Procedure (735 ILCS 5/2 — 619(a) (West 1996)). O’Brien attached his affidavit to the motion. In that affidavit, O’Brien averred that he was the executive vice president of Consulting Services of Frankfort, Illinois, Inc., and that,' in October 1993, he performed consulting services for Atlantic regarding work-place *15safety. O’Brien further stated that the plaintiff was not an employee of Consulting Services of Frankfort, Illinois, Inc., and that O’Brien was not an employee of Atlantic. Finally, O’Brien averred that he had no authority to hire or discharge employees of Atlantic in October of 1993. Based upon this affidavit, O’Brien’s motion sought dismissal of the complaint against him on the ground that he was not the plaintiff’s employer.
The plaintiff filed a response to O’Brien’s motion to dismiss, accompanied by the affidavits of the plaintiff and his counsel. The plaintiff’s affidavit stated that O’Brien worked out of Atlantic’s office at the power plant, O’Brien gave safety lectures at the job site on behalf of Atlantic, and O’Brien, on several occasions, drove the plaintiff from the job site to see physicians for his work-related injury. The affidavit of the plaintiff’s counsel stated that he possessed a letter written by O’Brien to one of the plaintiff’s treating physicians in which O’Brien called himself “Safety Supervisor, Atlantic Plant Maintenance,” and requested information about the plaintiff’s medical condition. On the basis of these affidavits, the plaintiff argued that he had sufficiently alleged that O’Brien had the authority to discharge the plaintiff on behalf of Atlantic. The plaintiff also cited two decisions of the Second District of the appellate court which held that a plaintiff may bring a retaliatory discharge action against a former supervisor individually, in addition to their former employer.
O’Brien filed a reply memorandum in support of his motion to dismiss. First, O’Brien pointed out that the conspiracy count of the plaintiff’s complaint, count III, was not directed at O’Brien and contained no prayer for relief against O’Brien. With regard to the retaliatory discharge claim, O’Brien argued that the plaintiff did not allege that O’Brien had been his supervisor. Further, O’Brien argued, the First District of the appellate *16court had held, contrary to the Second District, that a retaliatory discharge action may not be brought against parties other than the plaintiffs former employer.
The trial court granted O’Brien’s motion to dismiss. The court’s order first allowed the plaintiff leave to amend count III of his complaint instanter to include O’Brien in the prayer for relief under the conspiracy theory. The order then dismissed counts I, II and III as they pertained to O’Brien.
The plaintiff appealed to the appellate court. The appellate court, following the precedent of the First District, held that the only proper defendant in a retaliatory discharge action is the plaintiffs former employer, not the plaintiffs former supervisors. The court declined to follow the contrary holdings of the Second District. Accordingly, because the complaint did not allege that O’Brien had been the plaintiffs employer, the appellate court affirmed the dismissal of the retaliatory discharge claim against O’Brien. The appellate court also affirmed the dismissal of the conspiracy claim against O’Brien. 287 Ill. App. 3d 173.
We accepted the plaintiffs petition for leave to appeal to resolve the conflict in the appellate court on the retaliatory discharge issue. 166 Ill. 2d R. 315(a).
I. Retaliatory Discharge
We must decide whether a plaintiff may bring a retaliatory discharge action against the employee or agent of his former employer who effected the discharge on behalf of the employer. This court has not yet addressed this issue. As noted, the decisions of our appellate court on this issue are conflicting. The First District, in a line of cases beginning with Morton v. Hartigan, 145 Ill. App. 3d 417 (1986), has held that the only proper defendant in a retaliatory discharge action is the plaintiff s former *17employer. Morton, 145 Ill. App. 3d at 421-22; Balia v. Gambro, Inc., 203 Ill. App. 3d 57, 63 (1990), rev’d on other grounds, 145 Ill. 2d 492 (1991); Motsch v. Pine Roofing Co., 178 Ill. App. 3d 169, 176-78 (1989). The court in Morton looked to this court’s precedent which, it determined, required a narrow scope for the tort of retaliatory discharge. The Morton court concluded that allowing a retaliatory discharge action to be brought against a party other than the former employer would unduly expand the tort. Morton, 145 Ill. App. 3d at 421-22; see also Balia, 203 Ill. App. 3d at 63; Motsch, 178 Ill. App. 3d at 176-77.
The Second District of our appellate court has reached a contrary conclusion. In Fellhauer v. City of Geneva, 190 Ill. App. 3d 592, 600-02 (1989), rev’d on other grounds, 142 Ill. 2d 495 (1991), the court declined to follow Morton and held that an action for retaliatory discharge may be brought against not only the plaintiffs former employer, but also the employee or agent who performed the discharge. The Fellhauer court reasoned that, under principles of agency law, where the acts of an agent render the principal liable, the agent is also liable. The court further determined that holding the “active wrongdoer” liable, in addition to the employer, for retaliatory discharge would promote the deterrent goal of the tort. Fellhauer, 190 Ill. App. 3d at 602; see also Bragado v. Cherry Electrical Products Corp., 191 Ill. App. 3d 136, 143 (1989) (noting the holding in Fellhauer that a retaliatory discharge action may be brought against the agent or employee who performs the discharge, but finding that holding factually inapplicable).
The tort of retaliatory discharge has a relatively short history in this state. It was first recognized as a cause of action by this court in 1978 in Kelsay v. Motorola, Inc., 74 Ill. 2d 172 (1978). The Kelsay court noted that the long-standing general rule in this state was *18that an at-will employee may be discharged by the employer at any time and for any reason. The court determined, however, that a limited exception to this rule should be recognized when the reason for the employee’s discharge is the employee’s assertion of his or her rights under the Workmen’s Compensation Act. That Act, the court reasoned, was enacted to provide a comprehensive scheme for efficient and expeditious remedies for injured employees. The court concluded that “[t]his scheme would be seriously undermined if employers were permitted to abuse their power to terminate by threatening to discharge employees for seeking compensation under the Act.” Kelsay, 74 Ill. 2d at 181-82. Accordingly, the court held that a plaintiff who was terminated for pursuing workers’ compensation benefits could bring an action for retaliatory discharge against her former employer.
In Palmateer v. International Harvester Co., 85 Ill. 2d 124 (1981), the court was presented with the issue of whether the tort recognized in Kelsay should be applied beyond the workers’ compensation setting. There, the plaintiff alleged that he was discharged by his employer because he supplied information to law enforcement authorities that a fellow employee might be involved in illegal activities and agreed to assist in the investigation of the other employee. In a sharply divided decision, the court held that a retaliatory discharge action could be brought against an employer that fires an employee for volunteering information about possible criminal activity to law enforcement authorities. Palmateer, 85 Ill. 2d at 133. One of the dissenters in Palmateer was Justice Ryan, the author of the majority opinion in Kelsay. Justice Ryan wrote that the majority’s opinion in Palmateer was an unwarranted extension of the limited cause of action recognized in Kelsay. Palmateer, 85 Ill. 2d at 136 (Ryan, J., dissenting).
*19This court’s subsequent decision in Barr v. KelsoBurnett Co., 106 Ill. 2d 520 (1985), reaffirmed the narrow scope of the tort recognized in Kelsay. In Barr, the court refused to allow an action for retaliatory discharge because the discharged plaintiffs failed to allege a violation of a clearly mandated public policy. Barr, 106 Ill. 2d at 526. It had been argued in that case that the court’s decision in Palmateer signalled an expansion of the retaliatory discharge tort. The Barr court soundly rejected this proposition:
“Contrary to plaintiffs’ assertion, however, this court has not, by its Palmateer and Kelsay decisions, ‘rejected a narrow interpretation of the retaliatory discharge tort’ and does not ‘strongly support’ the expansion of the tort. The common law doctrine that an employer may. discharge an employee-at-will for any reason or for no reason is still the law in Illinois, except for when the discharge violates a clearly mandated public policy.” Barr, 106 Ill. 2d at 525.
Numerous subsequent decisions of this court have similarly maintained the narrow scope of the retaliatory discharge cause of action. For example, in Hartlein v. Illinois Power Co., 151 Ill. 2d 142, 159-61 (1992), this court declined to expand the tort to encompass a retaliatory discharge “process,” noting that, “[d]espite the revolutionizing effect of Kelsay, the common law doctrine that an employer may discharge an employee-at-will for any reason or for no reason remains the law in Illinois.” Likewise, in Zimmerman v. Buchheit of Sparta, Inc., 164 Ill. 2d 29, 45 (1994), the plurality traced this court’s “guarded development and narrow construction of the tort of retaliatory discharge” to reach the conclusion that it should not be expanded to encompass retaliatory discrimination or demotion. See also Balia v. Gambro, Inc., 145 Ill.. 2d 492, 501 (1991) (declining to extend the “limited and narrow” tort of retaliatory discharge to allow in-house counsel to sue former employer for retaliatory discharge); Fellhauer v. City of Geneva, *20142 Ill. 2d 495, 505, 508 (1991) (noting that the tort of retaliatory discharge is a “limited and narrow cause of action,” and finding that the “compelling circumstances” necessitating recognition of the action were not present in that case).
In this case, we are again presented with a request to expand the retaliatory discharge cause of action. The plaintiff asks that we allow this cause of action to be brought not only against the plaintiffs former employer, but also against the agent or employee of the employer who carried out the discharge of the plaintiff on the employer’s behalf. Given this court’s past precedent admonishing against the expansion of this tort, we decline to expand it in the manner proposed here by the plaintiff. The policy considerations that motivated this court to recognize a retaliatory discharge cause of action are adequately vindicated by allowing a cause of action against employers. Kelsay recognized a cause of action for retaliatory discharge in order to prohibit “employers” from abusing “their power to terminate.” Kelsay, 74 Ill. 2d at 182. Subsequent decisions of this court shaping the contours of this tort have likewise noted that “an employer could effectively frustrate a significant public policy by using its power of dismissal in a coercive manner.” (Emphasis added.) Fellhauer, 142 Ill. 2d at 508. Thus, this court has concluded, in certain “compelling circumstances,” recognition of a cause of action for retaliatory discharge is necessary to “vindicate the public policy underlying the employee’s activity, and to deter employer conduct inconsistent with that policy.” (Emphasis added.) Fellhauer, 142 Ill. 2d at 508; see also Hartlein, 151 Ill. 2d at 166 (stating that Kelsay prohibits an employer from utilizing an employee’s job as leverage to condition his exercise of rights under the Workers’ Compensation Act); Hinthorn v. Roland’s of Bloomington, Inc., 119 Ill. 2d 526, 529 (1988) (noting that retalia*21tory discharge actions are allowed to insure that sound public policy cannot be “frustrated by the actions of an employer” (emphasis added)).
This emphasis on tempering the power of the employer is not surprising. Logically speaking, only “the employer” has the power to hire or fire an employee. Obviously, an agent or employee of the employer may carry out that function on the employer’s behalf, but it is still the authority of the employer which is being exercised. If the discharge violated public policy, it is the employer who is rightly held liable for damages. The purpose underlying the recognition of retaliatory discharge actions is therefore fully served by allowing actions only against the employer.
The plaintiff contends, however, that the “deterrent effect” of the tort will be diminished if the employee or agent who “participated” in the firing is not also subject to liability. Imposing liability for retaliatory discharge on parties other than the employer is not necessary. The power to discharge rests with the employer. Subjecting the employer to liability for retaliatory discharge therefore acts to deter discharges which violate public policy. The plaintiff suggests that allowing other parties to be held liable is necessary because it may be those other parties who “devise the plan” to discharge the plaintiff for an unlawful reason. Even in the plaintiffs scenario, however, the discharge is still authorized by the employer. Moreover, from a practical perspective, if an agent or employee induces the employer to discharge another employee for an unlawful reason, and the employer is held liable for retaliatory discharge as a result, it is likely that the employer itself will act to “deter” that agent or employee from repeating such conduct.
Limiting the potential defendants in a retaliatory discharge action to employers is particularly appropriate in a case such as this where the alleged unlawful *22reason for the termination was the plaintiffs pursuit of workers’ compensation benefits. Under the Workers’ Compensation Act, workers’ compensation benefits are paid to an injured employee by the employer. See 820 ILCS 305/11 (West 1996). Presumably, the intent of an employer who adopts a policy of firing employees for seeking workers’ compensation benefits is to avoid having to pay such benefits to employees. Accordingly, it is only the employer who has a “motive” to fire an employee for seeking workers’ compensation benefits. The retaliatory discharge claim is therefore properly brought against the employer.
The plaintiff also contends that allowing retaliatory discharge actions to be brought against the agent or employee who carried out the firing is not an expansion of the retaliatory discharge tort, but is simply the application of general principles of agency law. We disagree. The plaintiff asserts that, under general principles of agency law, an agent whose tortious conduct renders the principal liable is also liable for his own tortious acts. This general rule may not, however, be logically applied to the tort of retaliatory discharge. As explained above, the power to hire and fire employees is ultimately possessed only by the employer. Consequently, the tort of retaliatory discharge may be committed only by the employer. The agent or employee who carries out the employer’s decision to fire will not be subject to personal liability for retaliatory discharge. We therefore disagree with the plaintiffs contention that his position in this case does not represent an expansion of the retaliatory discharge tort.
Accordingly, we hold that the only proper defendant in a retaliatory discharge action is the plaintiffs former employer. The plaintiffs complaint in this case alleged that he was employed by Atlantic, not O’Brien. The trial court’s' order dismissing the retaliatory discharge counts *23against O’Brien was therefore correct. The appellate court decisions in Fellhauer v. City of Geneva and Bragado v. Cherry Electrical Products Corp., to the extent they are inconsistent with this opinion, are overruled.
The trial court also dismissed the plaintiffs cause of action for civil conspiracy against O’Brien. We hold that this claim was properly dismissed.
Counts III and IV of the plaintiffs complaint purport to allege a conspiracy “to deny plaintiff his Workers’ Compensation Act benefits, and to hinder him and prevent him from pursuing his claim.” As originally pled, counts III and IV charged that defendants Sedgwick and Holden attempted to accomplish this objective by “falsely informing plaintiff on November 3,1993, that he would receive no benefits because he failed to show up for light duty work at Atlantic and ‘unilaterally elected to keep yourself off the job.’ ” In his motion to dismiss, O’Brien pointed out that the conspiracy counts of the plaintiffs complaint were directed only at defendants Sedgwick and Holden. Although the record does not disclose a motion to amend the complaint by the plaintiff, the plaintiff apparently moved to add O’Brien as a defendant in count III. The trial court granted the plaintiff leave to add O’Brien to count III. The trial court then dismissed the conspiracy claim against O’Brien.
The plaintiffs allegations fail to state a cause of action for conspiracy against O’Brien. The mere characterization of a combination of acts as a conspiracy is insufficient to withstand a motion to dismiss. See Hume & Liechty Veterinary Associates v. Hodes, 259 Ill. App. 3d 367, 369 (1994). In order to state a claim for civil conspiracy, a plaintiff must plead a combination of two or more persons for the purpose of accomplishing by concerted action either an unlawful purpose or a lawful purpose by unlawful means. Adcock v. Brakegate, Ltd., *24164 Ill. 2d 54, 62 (1994). We first note that, because the acts of an agent are considered in law to be the acts of the principal, there can be no conspiracy between a principal and an agent. See Salaymeh v. InterQual, Inc., 155 Ill. App. 3d 1040, 1043-44 (1987). The plaintiffs theory in this case is that O’Brien, at least for the purposes of discharging the plaintiff, acted as the agent of Atlantic. Accordingly, to the extent that the plaintiff seeks to allege a conspiracy between O’Brien and Atlantic, that claim must fail. With regard to the plaintiffs allegation of a conspiracy between O’Brien and Sedgwick and Holden, the plaintiff’s claim is entirely lacking factually. In Illinois, a plaintiff must plead the facts essential to his cause of action; unsupported conclusions are not enough. See Knox College v. Celotex Corp., 88 Ill. 2d 407, 422-26 (1981). Here, the plaintiffs complaint merely alleges that O’Brien conspired with Sedgwick and Holden to deny the plaintiff workers’ compensation benefits. The complaint provides no factual allegations to support that contention. The complaint does not allege any concert of action on the part of O’Brien, Sedgwick and Holden to achieve this purpose. In fact, the complaint does not even identify Sedgwick or Holden or the roles they played in this case. The complaint alleges simply that Sedgwick and Holden made certain statements to the plaintiff which, the plaintiff concludes, evidenced an intent to deny the plaintiff his workers’ compensation benefits. The complaint then makes the bald assertion that O’Brien “conspired” with Sedgwick and Holden. The plaintiffs conclusory allegations are not sufficient to state a cause of action for conspiracy against O’Brien. See In re Chicago Flood Litigation, 176 Ill. 2d 179, 202 (1997). The trial court therefore correctly dismissed the plaintiffs conspiracy claim against O’Brien.
For the foregoing reasons, we affirm the judgment of *25the appellate court which affirmed the dismissal of the plaintiffs complaint against O’Brien.