The cause was complications of lymphoma, said his former communications director, Bob Stevenson.

Mr. Rudman, a Korean War veteran and former amateur boxer, prided himself on his blunt-speaking adherence to centrist principles and his ­belief in bipartisan compromise as the underpinning of good government.

He served two terms in the Senate, but decided out of exasperation not to seek reelection in 1992, saying that the federal government was ‘‘not functioning’’ and that it was impossible to get anything done in a Senate rife with posturing and partisanship.

Before he left office he ­extended his fight against the federal budget deficit by joining with former senator Paul E. Tsongas, Democrat of Massachusetts, and former commerce secretary Peter G. Peterson in founding the Concord Coalition, a nonpartisan advocacy group on fiscal issues.

As a private citizen, he later served as cochairman of a federal commission on national ­security with former senator Gary Hart of Colorado. In a ­report released Feb. 15, 2001, seven months before planes crashed into the World Trade Center, the Pentagon, and a Pennsylvania field, the panel warned that ‘‘attacks against American citizens on American soil, possibly causing heavy ­casualties, are likely over the next quarter century.’’

Mr. Rudman was best known for two laws that sought to force the government to spend within its means: the Gramm-Rudman-Hollings Act of 1985 and the Gramm-Rudman Act of 1997. Those measures, sponsored with Senators Phil Gramm of Texas and Ernest Hollings of South Carolina, threatened automatic spending cuts if Congress and the president did not meet benchmarks on the road to a balanced budget.

While the laws helped hold down deficits, Republicans balked at raising taxes, and Democrats resisted limits on entitlements. The measures were amended and repealed ­before they could force huge spending cuts.

The failure of his efforts to control federal spending was one reason Mr. Rudman gave for retiring from the Senate.

‘‘I wasn’t sure the glory of being a senator meant much if we were bankrupting America,’’ he wrote in a 1996 memoir, ‘‘Combat: Twelve Years in the US Senate.’’

A signal moment in his Senate career came in 1987 when he served as vice chairman of the Senate contingent of the congressional investigation ­into the Iran-contra affair. He worked closely with Senator Daniel K. Inouye of Hawaii, the Democratic chairman, and joined in the majority report, opposed by House Republicans, which concluded that aides to President Reagan had knowingly violated the law by selling arms to Iran and using the money to aid anti-Communist rebels in Nicaragua.

In a confrontation with Lieutenant Colonel Oliver North, the Marine officer who played a central role in the ­affair, Mr. Rudman told him that he, too, believed that the United States should aid the rebels, known as contras, but that the American people and Congress had decided otherwise and made it a matter of law.

‘‘The American people have a right to be wrong,’’ he told North. ‘‘And what Ronald ­Reagan thinks or what Oliver North thinks or what anybody else thinks matters not a whit. There comes a point when the views of the American people have to be heard.’’

For all his work on fiscal and national security issues, Mr. Rudman said he regarded his role in the selection of David H. Souter for the Supreme Court as his proudest achievement. Souter had served as deputy when Mr. Rudman was attorney general of New Hampshire in the 1970s.

In an interview for this obituary in 2010, Mr. Rudman called Souter ‘‘an absolutely extra­ordinary member of the court’’ whose views, though he was part of the court’s liberal minority on social issues, ‘‘will become majority opinions and will become the law of the land.’’