By David Nather, CQ Staff

Fred Thompson wants to be seen as the true conservative in the Republican presidential field, but the former senator from Tennessee may be the one least likely to continue President Bush’s efforts to extend the powers of the presidency.

The reason has little to do with his ideological views and everything to do with his professional experience. As the counsel in the 1970s to Republicans on the Senate Watergate Committee and as the chairman in the 1990s of what is now the Senate Homeland Security and Governmental Affairs Committee, Thompson has much more experience than any other candidate in leading congressional investigations of presidents. He has spent much of his career, in fact, thinking like a prosecutor and standing up for Congress’ oversight responsibilities.

Even as a presidential candidate, Thompson comes off as the Republican most willing to defend congressional authority, particularly on issues such as whether a president should go to Congress before launching military strikes. “I don’t think anybody running for president should diminish the power of the office before he gets there,” he said during an October debate, “but I would say that in any close call, you should go to Congress, whether it’s legally required or not.”

GETTY IMAGES / JOSHUA LOTT (STAR TURN: Thompson, a former TV actor and senator, makes his pitch in Sioux City, Iowa, on Sept. 7.)

That doesn’t mean a President Thompson would begin giving away his powers on his first day in the White House. In explaining how he would deal with terrorism suspects, for instance, he is careful to preserve all his options for interrogation techniques and has not ruled out the use of the technique known as waterboarding, which has come under strong criticism as being tantamount to torture. “If we’re facing the imminent loss of innocent American lives . . . the measures have to meet those circumstances,” Thompson said on NBC’s “Meet the Press” in November.

And as one of the main authors of the 2002 legislation that created the Department of Homeland Security, Thompson defended Bush’s insistence on having maximum flexibility on hiring and salary decisions for the department’s employees. He claimed that a Democratic alternative “would actually diminish the president’s national security authority that other presidents have had.”

In general, though, Thompson has been silent on most issues of executive power since he entered the presidential race in September. And he doesn’t have a history of being a booster of presidential authority for its own sake. His frame of reference for most of his congressional career came from his oversight activities, starting with the Watergate scandal, which ended Richard Nixon’s presidency, and continuing with his 1997 investigation of alleged violations of campaign finance laws by Bill Clinton’s administration.

In both cases, Thompson showed no special concern for undermining the powers of the presidency. Most of his statements at the time, in fact, were about the need to fulfill Congress’ oversight responsibilities. So it will take one spectacular, 180-degree turn for Thompson, if he is elected, to become a champion of presidential authority and reject everything he has said in the past about congressional oversight. So far, as a presidential candidate, he hasn’t attempted it.

“He’s made his career as a hard-hitting attorney, and that’s how he approached it,” said Republican Sen. Robert F. Bennett of Utah, who served on Thompson’s committee during the campaign finance investigation.

In Thompson’s 1975 book about the Watergate hearings, “At That Point in Time,” he never sounds agonized over his role in the events that led to a constitutional showdown and a weakened presidency. “Looking back, I wonder how I could have failed to realize at once, that Friday afternoon, the significance” of the discovery of Nixon’s White House taping system, Thompson wrote. “As a trial lawyer, I focused on the fact that the tapes could resolve conflicts in testimony; I did not foresee the extraordinary constitutional confrontations that emanated from them.”

As for Nixon, Thompson wrote, “He undoubtedly felt that the institution of the presidency, and he as the holder of that office, were so powerful that no force on Earth was strong enough to make him relinquish the tapes. In this, the master politician misjudged Congress, the Supreme Court and the American people.”

Two decades later, as a candidate for the Senate in 1994, Thompson adopted a more populist tone, calling for a part-time Congress that would be in session for only half the year — turning it into more of a “citizen legislature.” If that proposal had become a reality, it would have given Congress less time and ability to conduct oversight, notes former Republican Rep. Mickey Edwards of Oklahoma, a lecturer at the Woodrow Wilson School of Public and International Affairs.

Thompson’s flirtation with a reduced role for Congress ended quickly after he became a member. In 1997, as chairman of what was then called the Senate Governmental Affairs Committee, he conducted 33 days of hearings into the Clinton administration’s campaign finance scandals.

Thompson took some heat from his Republican colleagues for supporting calls for a broader investigation, including probes of congressional campaigns in both parties. But he also scorned the Clinton administration’s attempts to claim executive privilege to withhold documents and declared that “we have an oversight responsibility” to make sure the executive branch enforces the laws.

Thompson also praised President Ronald Reagan for cooperating with Congress during the 1987 investigation of the Iran-contra scandal, noting that Reagan “opened up all the files and records. Didn’t claim executive privilege, didn’t claim attorney-client privilege, even let the committee . . . look at portions of the president’s own diary. Nobody took the Fifth, and nobody left the country.”

And in 1999, Thompson was a vocal advocate of Congress’ power to authorize wars, opposing John McCain ’s resolution that would have given Clinton the authority to send ground troops to Kosovo to supplement NATO’s air strikes. The McCain resolution “would grant the president authority he has not sought, based on the War Powers Resolution he does not recognize, to fight a ground war he has promised he will not undertake,” Thompson said during the Senate floor debate. “If the commander in chief decides that we need ground troops in Yugoslavia, then he should come to the Congress and request them.”