East was a protégé of conservative Senator Jesse Helms. In 1966, East ran unsuccessfully for a vacancy in the United States House of Representatives in a special election, a race won by Walter B. Jones, Sr.. In 1980, with the benefit of Ronald Reagan's North Carolina influence, East narrowly defeated incumbent Democratic Senator Robert Burren Morgan, largely on the strength of political advertising about Morgan's involvement with the turnover of the Panama Canal to the government of Panama. In the Senate, he earned a reputation as a staunch social conservative, especially on the issue of abortion. Alongside Jesse Helms, East led opposition to the bill to create a federal holiday to honor Martin Luther King, Jr. in 1983. East was also a national security hawk, and was a member of the Judiciary Subcommittee on Security and Terrorism along with Orrin Hatch and Jeremiah Denton. The committee is notable for its accusations of Soviet infiltration of left-wing think tanks, publications and activist groups such as the Institute for Policy Studies and the magazine Mother Jones. East's primary national security staffer on the committee, Samuel T. Francis, later a prominent columnist for the Washington Times, has been cited as an intellectual fore-bearer of the alt-right movement. In 1986, he announced that he would not seek re-election, and would instead return to his teaching position. That summer, East, suffering from hypothyroidism, killed himself at his North Carolina home.
Death
On Friday, June 27, 1986, Senator East completed work on the book galleys of his collected essays. He met with Supreme Court nominee Antonin Scalia. Then, commitments met, the Senator drove to Greenville with his aide, John Petree, and arrived home about noon on Saturday. Petree stayed with him until daughter Kathryn arrived for a visit. Kathryn left her father "in good spirits" about midnight. Petree returned to East's house on Sunday morning, June 29. He found the front door ajar. The senator was dead in his garage, a victim of suicide by carbon monoxide poisoning. North Carolina Governor James G. Martin appointed U.S. Representative James Thomas Broyhill to serve out the rest of East's term. Broyhill was later defeated in his election bid in November 1986 by former Democratic GovernorTerry Sanford. East is buried in Arlington National Cemetery.