As one of the most left-leaning Republicans of the House, Case was supportive of Harry S. Truman's Fair Deal and Marshall Plan programs.

After an unsuccessful attempt to run for the Republican nomination for the 1953 New Jersey gubernatorial election, Case became president of the Ford Foundation's Fund for the Republic.

In the Senate, Case was one of the biggest supporters of Democratic presidents John F. Kennedy and Lyndon B. Johnson's New Frontier and Great Society programs.

In 1978, Case was defeated in the Republican primaries for the United States Senate by Jeffrey Bell, who ran to his right.

[2] His father was also a staunch Republican who even canceled his subscription to The New York Times after it endorsed Woodrow Wilson in the 1912 presidential election.

[3] After serving at Six Mile Run Reformed Church in Franklin Park, his father accepted a position as pastor in Poughkeepsie, New York, in 1907.

[5] His class predicted he would become vice president of the United States, adding, "His good nature, however, and his stubborn hair will keep the Cabinet happy and harmonious.

[5] His father died the year before, and Case helped pay for his tuition by working part-time jobs, including playing the pipe organ in church on Sundays.

[6] The couple remained married until his death; they had two daughters, Mary Jane and Ann, and one son, Clifford Philip III.

"[4] A strong supporter of the Civil Rights Movement, he voted in favor of an anti-poll tax measure, a proposal to prevent segregation in the Women's Reserve of the Coast Guard, and the creation of a Fair Employment Practices Commission to prohibit discrimination in the workforce.

[4] He also opposed the establishment of a permanent House Un-American Activities Committee and the overriding of President Harry S. Truman's veto of the Immigration and Nationality Act of 1952.

[6] In August of that year, he resigned from the House to become president of the Ford Foundation's Fund for the Republic, an organization dedicated to protecting freedom of speech and other civil liberties in the United States.

[9][10] A conservative faction within the Republican Party unsuccessfully attempted to force Case off the ballot, also proposing a write-in campaign for former U.S. Representative Fred A. Hartley Jr., co-author of the Taft-Hartley Act.

From 1973 to 1978, Case, along with fellow Republican senators Jacob Javits and Edward Brooke, is seen by GovTrack as being to the left of Democrats like Hubert Humphrey, George McGovern, Edmund Muskie and Gaylord Nelson.

Despite his liberalism, Case saw himself as a conservative in the vein of Edmund Burke, Benjamin Disraeli, Winston Churchill and the Federalist Papers.

Case was a co-author of the Case-Zablocki Act of 1972 which required that executive agreements by the president be reported to Congress in 60 days.

In a country as wealthy and resourceful as ours, there is no reason why every citizen, rich or poor, young or old, working or unemployed, should be denied the right to good healthcare.

[23]Case sought a fifth Senate term in 1978, but lost the Republican primary to Jeffrey Bell, an anti-tax conservative.

Case criticized Bell's support of a tax cut bill introduced by Jack Kemp, believing that it would cause tremendous inflation.

I hope that as we honor Cliff Case today we can learn from the man and his principles which helped to chart a certain portion of our Nation's history——for they are timeless in their simplicity and strength.

[25][better source needed]His grandson, former Clinton Mayor Matthew Holt, was elected to the Hunterdon County Board of Chosen Freeholders in 2005.