Can Congress matter?

Correction: Because of reporting errors, the quotation, ''Congress cut off money to Vietnam in 1975 and the helicopters were circling over the embassy roof," was incorrectly attributed to Louis Fisher in the story ''Can Congress Matter?" in Sunday's Ideas section. It was said by David Mayhew, a political scientist at Yale University. Also, Louis Fisher's surname was misspelled as Fischer.

IN 1973 THE historian Arthur Schlesinger Jr. published a book called ''The Imperial Presidency," tracing the way in which the White House had, over the course of American history, grabbed more and more power until it threatened to overwhelm the rest of the federal government. Then-president Richard Nixon-who carried out a secret bombing campaign of Cambodia, eavesdropped on his domestic rivals, and impounded federal funds that Congress had earmarked for programs he didn't like-was to Schlesinger only the latest and most brazen example.

President George W. Bush, say his Democratic critics (and even a few Republicans), has demonstrated Caesar-like proclivities of his own. The past week's confirmation hearings for Supreme Court nominee Samuel A. Alito Jr. reflected increasing concerns in Congress that Bush is pushing the envelope of presidential power like few before him. He has approved warrantless surveillance of Americans by the National Security Agency, issued a ''signing statement" reserving the right to waive a congressionally mandated ban on torture, and attempted to game the federal courts in cases involving terror detainees.

With John Roberts, a former White House lawyer known for an expansive view of presidential prerogative, now presiding as chief justice, the widely-predicted confirmation of Alito, whose record suggests a similar bent, could well make the Supreme Court even more accommodating of executive power.

Yet the branch of government Schlesinger exhorted to resist the executive's slow-motion coup was not the Supreme Court. It was Congress. And although throughout most of Bush's presidency the legislative branch has been, in the words of Thomas Mann, a government scholar at the Brookings Institution, ''remarkably weak and supine," there are signs that the president's assertions of power have finally roused the nation's legislature. The same day that it overwhelmingly approved the defense bill including the anti-torture amendment, Congress refused to give the administration its desired extension of the USA Patriot Act. And several members of Congress, most importantly Senate Judiciary Committee Chairman Arlen Specter, have called for hearings on the NSA's surveillance program.

But even as Congress bestirs itself to seek limits on the president's power, the question remains: How much can it do? Over the last half century, historians and political scientists observe, Congress's clout has waned as dramatically as the executive's has grown, especially in national security matters. And Congress itself is largely to blame.

Instead of jealously guarding its institutional prerogatives, Congress has been complicit in the diminution of its powers, in a way that seems to run counter to the very logic of the Constitution's system of checks and balances. Whether Congress manages to impose its power over the executive branch, then, depends on whether the body has the will to reverse its own history.

The Founding Fathers intended for the president to serve, in effect, under Congress, but presidents have been straining at the constitutional leash since the creation of the office. Thomas Jefferson, an avowed critic of executive power in theory, didn't consult with Congress before approving the Louisiana Purchase or waging war against the Barbary Pirates. James K. Polk maneuvered the country into war with Mexico, only seeking congressional approval after the fact. In the opening months of the Civil War, Abraham Lincoln essentially ran the government without Congress, taking actions he later acknowledged were most likely unconstitutional.

Historically, when the country feels threatened-by Southern secession, for example, or the attack on Pearl Harbor or the Great Depression-the president and the executive branch have tended to grow in influence. Bush's presidency fits that pattern. ''After 9/11 Bush enjoyed tremendous latitude to do what he wanted," says William Howell, a Harvard government professor who has just completed a book about congressional checks on presidential power. Congress gave the president broad discretion during the lead-up and early months of the war in Iraq and agreed to the creation of the Department of Homeland Security, an enormous addition to the executive branch.

Traditionally, as the sense of threat receded, so did the deference paid the president. But things changed with the Truman administration, in foreign affairs in particular. In 1950 Truman sent troops to Korea to fight in a war that Congress never declared. Truman was the first Cold War president, and the first president of the nuclear age. According to Andy Rudalevige, a Dickinson College political science professor and author of the recently published book ''The New Imperial Presidency," during that era ''you had a sense of crisis becoming business as usual, so presidential power became business as usual."

Truman's successors, especially Kennedy, Johnson, and Nixon, continued the expansion of the national security establishment Truman had started. With the CIA, the National Security Council, the National Security Agency, and other intelligence-gathering organizations, the White House had access to information largely unavailable to Congress, a decided advantage in security debates between the branches.

All of this complemented the growing clout of domestically-focused executive agencies like the Federal Trade Commission, the National Labor Relations Board, and the Securities and Exchange Commission, which moved beyond merely implementing policy to making it, issuing regulations that determined in increasing detail the way Americans lived and worked.

In the 1970s, in the wake of Vietnam and Watergate, the War Powers Resolution reasserted congressional control over the decision to go to war, the Foreign Intelligence Surveillance Act (the law Bush now stands accused by Democrats of having broken) limited the government's ability to eavesdrop on Americans, and the Congressional Budget Act strengthened Congress's hand in the budget process. But Congress, as often as not, has failed to follow through with the oversight mandated by those laws. As a result, the shifting balance between the legislative and executive branches has been as much a matter of Congress's conceding power as the president's seizing it.

Congress has managed to get the commander in chief to honor the War Powers Resolution only once, in an obscure 1975 Marine action to recapture a tanker seized by the Khmer Rouge off the coast of Cambodia. Presidents since then have on occasion sought some form of congressional approval before going to war (as in both Gulf wars), but just as often they have not (as in Kosovo and Haiti). In none of those cases was there a formal declaration of war. Indeed, in 1995 Republican leaders in both the House and the Senate called for the repeal of the resolution altogether. (Newt Gingrich, speaking on the House floor, acknowledged it was ''an unusual moment" when he found himself appealing to increase the power of Bill Clinton.)

Two factors explain this lack of congressional backbone, say most scholars. First, the two political parties have grown more polarized in recent decades and institutional allegiance has faded in the face of stronger partisan loyalties. Congressmen think of themselves as Republicans or Democrats first, and members of Congress second. ''Over the course of the 20th century," says Sarah Binder, a congressional scholar at George Washington University, ''the president really has become the head of the political party, and the fortunes of the party are really tied to the fortunes of the president."

Adding to this effect, Bush is the first Republican president since Dwight Eisenhower to enjoy the support of a Republican-controlled Congress. And his Republican majority has so far been a notably disciplined one. Since 1994, the Republican leadership has cut back the power of congressional committees and trimmed committee staffs, centralizing power so that the party, both in the executive and legislative branch, is more likely to speak with one voice. ''The Republicans had been out of power for so long," says Mann. ''That made them more determined to make the most of it when they took over. They felt that party and the agenda trumped the institution."

The other factor is that legislators usually see little electoral gain from an emphasis on foreign affairs. ''Congress has a tremendous incentive to keep and protect its domestic powers," says Gordon Silverstein, a political scientist at the University of California at Berkley, since that means controlling the sort of entitlement and infrastructure programs that keep their constituents happy. ''But Congress has negative incentives in the realm of war powers. If we go to war and win, the president is the hero, not Congress, but if we lose Congress can get blamed." It's easier, then, for Congress to step aside and let the president take the risk.

Short of impeachment, which in theory is reserved for exceptional situations, Congress does have tools it can use to limit the president. It can hold hearings and conduct investigations. It can make life difficult politically for the White House. And it still holds the power of the purse. As Louis Fischer, a specialist in the separation of powers at the Congressional Research Service, points out, ''Congress cut off money to Vietnam in 1975 and the helicopters were circling over the embassy roof."

Fischer, for one, hopes to see a more commanding Congress. He argues the stakes are much higher than simply that of a turf war between different government branches. ''We have to not buy into the notion that because there's a national emergency you should suspend deliberation," Fischer says. ''In times of emergency you need public deliberation, otherwise you have a handful of people, often with not very good information, making decisions that are very hard to reverse."

Drake Bennett is the staff writer for Ideas. E-mail drbennett@globe.com.