[3] McCloskey continually won re-election until 1982, when he unsuccessfully sought the Republican nomination to represent California in the United States Senate.

He was awarded the Navy Cross and Silver Star decorations for heroism in combat and two Purple Hearts as a Marine during the Korean War.

"[13] McCloskey was the first member of Congress to publicly call for the impeachment of President Nixon after the Watergate scandal and the Saturday Night Massacre.

[18] In January 1980, McCloskey was one of six members of an official bipartisan delegation of the House of Representatives appointed by Speaker Tip O'Neill to visit Lebanon, Syria, and Israel.

[19] In Beirut the delegation met with Palestine Liberation Organization chairman Yasir Arafat with a plan to conclude the trip with a meeting with Prime Minister Menachem Begin and other Israeli leaders in Jerusalem.

Jerry Falwell for support for the June 7, 1981, Israeli airstrike on an unfinished Iraqi nuclear reactor and added, "We have to respect the views of our Jewish citizens, but not be controlled by them.

"[20] However, he also predicted that criticism by B'nai B'rith officials in California would harm his prospects of winning the 1982 Republican Senate primary there.

The California Republican Senatorial primary that year was a contentious battle among the major candidates in the 12-person GOP field, featuring mainly Reps. McCloskey, Bob Dornan, Barry Goldwater Jr. (son of Arizona Senator and 1964 Republican presidential nominee Barry Goldwater), Maureen Reagan (daughter of then-President Ronald Reagan), San Diego Mayor Pete Wilson, former Rep. John G. Schmitz, and Los Angeles Chamber of Commerce president Ted Bruinsma.

[24] Earlier in the year, he formed a group called the "Revolt of the Elders" to recruit a viable primary candidate to run against Pombo.

[30] During the 2006 primary campaign there was controversy over what McCloskey allegedly said about the Holocaust during his keynote address, titled "The Machinations of the Anti-Defamation League", to the May 2000 Institute for Historical Review conference.

[34][35] According to Hertsgaard, McCloskey "told the delegates, 'I may not agree with you about everything I've heard today,' before he reiterated a core point of his speech—that the right for anyone to question what is said about the past is basic to freedom of thought in America.

[36] Members of the student government also tried to pressure McCloskey to remove an article by former US diplomat George Ball from his course syllabus and "add materials reflecting pro-AIPAC views.

[37] According to a disputed transcript of an event fourteen years later, McCloskey stated that two thousand people attended the 1986 debate which took place in San Francisco.

[39] McCloskey and former Rep. Paul Findley (R-Ill.) helped arrange a June 8, 1991, White House ceremony during which forty-two surviving crew members of the USS Liberty, an intelligence ship attacked by Israeli forces in 1967, were belatedly presented the Presidential Unit Citation awarded, but never presented, to the ship's crew by President Johnson in 1968.

[40] The ceremony took place on the 24th anniversary of the incident, which killed thirty-four Americans, and was attended by White House Chief of Staff John Sununu and National Security Adviser Brent Scowcroft.

[40] The Anti-Defamation League (ADL) expressed concerns about whether the event was held "to give a stamp of approval to those seeking to malign Israel".

[40] The ADL singled out the participation of McCloskey and Findley as "staunch critics of Israel" and "expressed concern with their involvement 'and the sanction given by the White House of such rhetoric.'

McCloskey and Robertson were part of a contingent of 71 Marine officers and 1,900 enlisted men shipped to Korea aboard the USS General J. C. Breckinridge to serve as replacements.

Rather than being a combat veteran, Robertson had been shipped to Japan right off the USS Breckinridge, then spent most of his time when returned to Korea posted at the safe harbor of the Division Headquarters.

Documentary evidence uncovered by McCloskey revealed that his father, Senator Robertson, thanked Marine Commandant Robinson for getting his son out of combat.

By the time of the libel trial, which was scheduled for Super Tuesday, many other Marine officers were prepared to testify that Robertson had avoided combat duty.

[9] An opponent of the Iraq War,[47] McCloskey broke party ranks in 2004 to endorse John Kerry in his bid to unseat George W. Bush as President of the United States.

In an email and letter to the Tracy Press, McCloskey stressed that the "new brand of Republicanism" had finally led him to abandon the party that he had joined in 1948.

[50] As Democrat Joe Biden won the state's popular vote, McCloskey became one of California's 55 members of the Electoral College.