pre-termination hearing. In order to demonstrate this essential element of her case she was required to show that she had “a constitutional property interest in continued employment at the Department of Corrections.”1
We have discussed whether an alleged “property” interest may be found under the due process clause in various factual contexts. See, e.g., Patterson v. Portch, 835 F.2d 1399, 1404-1405 (7th Cir.1988); Fleury v. Clayton, 847 F.2d 1229, 1231-1233 (7th Cir.1988); Yatvin v. Madison Metropolitan School District, 840 F.2d 412, 416-417 (7th Cir.1988). A useful starting point in determining whether Common possessed a constitutionally protected “property” interest in continued employment is the United States Supreme Court’s decision in Board of Regents v. Roth, 408 U.S. 564, 577, 92 S.Ct. 2701, 2709, 33 L.Ed.2d 548 (1972), which explained:
“To have a property interest in a benefit, a person must have more than an abstract need or desire for it. He must have more than a unilateral expectation of it. He must, instead, have a legitimate claim of entitlement to it.
Property interests, of course, are not created by the Constitution. Rather, they are created and their dimensions are defined by existing rules or understandings from an independent source such as state law — rules or understandings that secure benefits and that support claims of entitlement to those benefits.”
“[Property interests may be a matter of statutory entitlement,” or “they may also arise from mutually explicit understandings.” Davis v. City of Chicago, 841 F.2d 186, 188 (7th Cir.1988) (citations omitted). In order to provide parties with guidance concerning the type of evidence of custom or policy which can be utilized to demonstrate a “mutually explicit understanding,” the Supreme Court has pointed to the analogous doctrines of “implied contracts” arising from parties mutual understandings and of the “common law of a particular plant’ that may supplement a collective-bargaining agreement.”2 See Jago v. Van Curen, 454 U.S. 14, 18-20, 102 S.Ct. 31, 34-35, 70 L.Ed.2d 13 (1981); Perry v. Sindermann, 408 U.S. 593, 601-602, 92 S.Ct. 2694, 2699-2700, 33 L.Ed.2d 570 (1972). A party utilizing such evidence of custom or policy to establish a mutually explicit understanding capable of giving rise to a legitimate claim of entitlement in continued employment, must demonstrate “an ‘expectation ... that was legally enforceable’, a mutually binding obligation.” Upadhya v. Langenherg, 834 F.2d 661, 665 (7th Cir.1987) (citations omitted). This expectation must be something which “ ‘is securely and durably yours under state (or ... federal) law, as distinct from what you hold subject to so many conditions as to make your interest meager, transitory, or uncertain.’ ” Yatvin, 840 F.2d at 417 (quoting Reed v. Village of Shorewood, 704 F.2d 943, 948 (7th Cir.1983)). It is clear that “a merely subjective and unilateral expectancy is not protected by due process.” Davis, 841 F.2d at 188 (citation omitted).
Our previous cases construing the “property” interest in continued employment enjoyed by certain Illinois public employees have found a distinction between probationary employees, who do not possess such an interest, and employees who have completed their probation period, who do enjoy this right. See Fontano v. City of Chicago, 820 F.2d 213, 214-216 (7th Cir.1987); Webster v. Redmond, 599 F.2d 793, 799-801 (7th Cir.1979). As the district court properly noted, this same distinction applies to deputies employed by the Cook County Department of Correction. See Common v. Williams, No. 86 C 5169, slip op. at 5 (N.D.Ill. November 30, 1987) [available on WESTLAW, 1987 WL 26152] (citing Ill.Ann.Stat. ch. 125, ¶ 160 (Smith-Hurd, Supp.
1
Common makes no allegation that she was deprived of a constitutionally secured "liberty” interest.
2
Perry v. Sindermann, 408 U.S. 593, 602, 92 S.Ct. 2694, 2700, 33 L.Ed.2d 570 (1972) (citing
United Steelworkers v. Warrior and Gulf Navigation Co., 363 U.S. 574, 579, 80 S.Ct. 1347, 1351, 4 L.Ed.2d 1409 (1960)).