In an airport in the Russian city of Perm, a minor diplomatic crisis broke out last August. In violation of an international treaty, local border police refused to allow the plane of Senators Richard Lugar and Barack Obama to depart without being inspected. Instead of pitching a fit, Lugar, the powerful Republican chairman of the Foreign Relations Committee, curled up on a chair—ignoring the overpowering smell of a broken toilet—and took a nap. The Russians eventually backed down. "He is a quiet, intelligent, steady force," says former Nebraska Senator Bob Kerrey, Lugar's former colleague. But make no mistake, Kerrey adds, "he's unmovable when he reaches a conclusion about what ought to be done."

America's Best Senators Those who do, and don't, make a difference in the U.S. Senate The Best Senators Thad Cochran Kent Conrad Dick Durbin Ted Kennedy Jon Kyl Carl Levin Richard Lugar John McCain Olympia J. Snowe Arlen Specter The Worst Senators Daniel Akaka Wayne Allard Jim Bunning Conrad Burns Mark Dayton From the TIME Archive Nov. 5, 1979 The Kennedy Challenge More than a quarter century ago, TIME covered the presidential campaign of Senator Ted Kennedy, "the last of the Kennedy brothers, the youngest, the most vulnerable, the most thoroughly political"

That level of conviction helps when, as one of America's leading internationalists, you're a defender of free trade and an enemy of farm subsidies, yet you represent a state dominated by manufacturing and farming. It's also a bonus that Lugar's thinking has often proved to be ahead of the curve. In the 1980s, Lugar led the push for democracy in the Philippines and South Africa when the Reagan Administration was still backing undemocratic regimes there. And Lugar, 74, has long been an ardent advocate of developing alternative fuels as a way to wean the U.S. from foreign oil—an approach endorsed by Bush in January.

Lugar's signature achievement was to recognize the dangers of loose nukes 10 years before 9/11. With Democrat Sam Nunn, he sponsored legislation that funded the removal of all nuclear weapons from Ukraine, Belarus and Kazakhstan and the deactivation of 6,828 nuclear warheads throughout the former Soviet Union. In recent years, Lugar has expanded his non-proliferation efforts to help secure shoulder-launched missiles, a favorite of terrorists, and chemical-weapons depots, like one near the Kazakhstan border that contained 1.9 million Sarin gas shells. He is withholding support for Bush's recent nuclear deal with India until hearings he has called determine whether letting Delhi import technology to build reactors would create a new proliferation problem.