A ruling that Illinois real estate brokers and salesmen can be licensed only by the state - not by its political subdivisions - has survived a challenge in the Supreme Court from the Chicago suburb of Evanston.

In an action last week, the justices let stand an October 1977 ruling by the Illinois Supreme Court that under a 1974 law, the state pre-empted the power to license brokers.

In an unsuccessful petition for U.S. Supreme Court review of the decision, the city of Evanston said the state court had removed "the only viable sanction in local fair housing ordinances against racial discrimination on the part of real estate brokers."

After the 1974 law was adopted, about 25 Illinois cities and villages, including Chicago, adopted ordinances requiring brokers to obtain municipal licenses as a condition of doing business.

Cooke County brokers sued for an injunction and for repayment of fees they had paid to municipalities ($25 a year in Chicago).

Evanston filed a counter claim asserting that the cities had independent authority to license brokers.

Evanston also asserted that it needed to license brokers in order to enforce its local housing anti-discrimination ordinance. The state court rejected this assertion as being "without merit."

Such ordinances can be enforced without municipal licensing, the court held.

In its petition to the U.S. Supreme Court, Evanston claimed that the state court had ignored the requirement in the federal Constitution for equal protection of the laws.

The city charged that the state, which has no fair housing law as such, "has a history of total failure in the fair housing field." The petition added: "The real estate industry, which historically has been in the forefront of encouraging and promoting discrimination, has succeeded at the level of the Illinois General Assembly in removing the most meaningful sanction against their continued exploitation of minority groups."

The petition also alleged that the state court ruling would "triple the fair housing ordinance by removing the sanctions against real estate brokers in the most sensitive of areas, i.e., license suspension and revocation . . ." Thus, Evanston contended, "for all practical purposes real estate brokers are now free to discriminate at will."

The city also argued that the state court's "emasculation of the fair housing ordinance would render meaningless the heretofore unsuccessful effort to maintain integration and open housing in this community."