Former Sen. Clifford P. Case (R-N.J.), a patrician statesman who represented his state in the U.S. Senate for 24 years and was ranking member of the Foreign Relations Committee before being defeated in his party's 1978 senatorial primary, died of lung cancer Friday at Georgetown University Hospital. He was 77. He maintained homes in Washington and Rahway, N.J.

During his years in the Senate and five terms in the House of Representatives before that, he became identified with his party's progressive wing. He generally voted for pro-labor and liberal domestic measures in both houses. One reporter called him a "traditional liberal in Republican clothing."

He became known as one of the Senate's strongest supporters of the state of Israel and fought the Carter administration's program of selling warplanes to Egypt and Saudi Arabia.

He supported the Panama Canal treaties and helped guide them to ratification. His other positions included a critical view of this nation's actions in Southeast Asia, a jaundiced view of the operations of our intelligence agencies, and a belief that Congress should have a greater role in the conduct of foreign affairs.

He joined key Democrats in the early 1970s in legislative efforts to curb the power of the president to wage war, and probably received the widest publicity of his Senate career. The "Case Act" of 1972 said the president had to report any executive agreement reached with a foreign country to the Congress within 60 days.

In 1973, he and Frank Church, the former Democratic senator from Idaho, cosponsored legislation cutting off appropriations for American combat anywhere in Indochina.

During 1974 debate on the operations of the Central Intelligence Agency, he addressed the Senate floor saying that "Covert activities . . . should be regarded as wrong."

Sen. Case sought a fifth Senate term in 1978, but according to one reporter covering the race, "treated the primary more as an annoyance than a contest, spending more time in Washington than in New Jersey even in the last weeks . . . ."

Although favored by all the polls and boasting the endorsement of party leaders in the state, Sen. Case was defeated for renomination in the primary by Jeffrey Bell, 34, who had been a member of Ronald Reagan's 1976 campaign staff and was making his first bid for public office. Bell was defeated in the general election by Bill Bradley.

In recent years, Sen. Case had been of counsel to the Washington office of a New York City law firm, and divided his time between Washington and New Jersey.

Sen. Case was born in Franklin Park, N.J., and was a 1925 graduate of Rutgers University where he was a member of Phi Beta Kappa. Three years later he earned a law degree at Columbia University.

He began his political career in 1937 when he won election to the Rahway common council. He was elected to Congress in 1944, and won reelection four times, by wide margins. While in the House, he sponsored an antilynching bill, introduced bills to liberalize immigration policy, and supported civil rights.

He resigned from Congress in August 1953 to become president of the Fund for the Republic, a non-profit organization he headed until entering the Senate race in March 1954.

Survivors include his wife, the former Ruth Smith of Washington and Rahway; two daughters, Mary Jane Weaver of Rahway, and the Rev. Ann Holt of Annandale, N.J.; a son, Clifford P. III, of New York City; three sisters, Elisabeth B. Case of Deep River, Conn., Harriett Phelps of Camden, Me., and Jeannette B. Gifford of New Haven, Conn., and seven grandchildren.