Between Congress and the president, a power seesaw

American involvement in Iraq appears to be an unresolvable dilemma: the United States can neither stay in nor get out. It cannot stay in because the public will not support it. It cannot get out because, after four years there, the US has wrecked the country. It would be unconscionable now simply to walk away and leave a nation of impoverished Iraqis among the ruins.

America cannot start writing a new policy on a clean slate. But what it can do is adjust the imbalance of power between the executive and legislative branches. Too much deference to the White House got the US into this predicament. A more-assertive Congress might help bring about a solution, and more important, avoid a similar situation in the future.

The Iraq war represents a constitutional failure of American government, but it was not the institutions of government that failed; it was the people who were supposed to make those institutions work. The Constitution provides for a separation of powers among the legislative, executive, and judicial branches. It is the separation of powers that creates the crucial checks and balancesthat enable one branch to keep another in line.

A good deal of the thinking that went into this structure was based on skepticism and distrust. From long experience, the framers of the Constitution were skeptical and distrustful of power, and they wanted to build this into the new government.

Perhaps the biggest failure with respect to Iraq was in Congress. Members were far too deferential to the White House; they failed to question President Bush's reactions to 9/11 as they were duty-bound to do. Among Republicans on Capitol Hill, there was an exaggerated sense of party loyalty to the president. Among both parties, there was an exaggerated sense of partisanship.

The party system and the separation of powers are incompatible. Parties do not work well without cohesion and discipline. The separation of powers does not work well without independence. This conflict was foreseen by the framers. In one of the Federalist papers, James Madison warns against "the pestilential influence of party animosities."

The Constitution has been called "an invitation to struggle" between the president and Congress for the control of foreign policy. On Iraq, Congress did not accept the invitation. Republicans reveled in Mr. Bush's popularity. Democrats were afraid of it. Only after the public began to turn against the war did Congress began to follow. Meanwhile, the president was left unchecked.

The history of the constitutional struggle between president and Congress is a seesaw with first one branch up and then the other. Congress probably reached its post-World War II high at the end of the Vietnam War when it used its control of money to force the US to end its support of South Vietnam. When President Johnson left office in 1969, a congressional observer remarked that it would take to the end of the 20th century to restore presidential powers to where Johnson found them.

Bush became president in 2001 determined to hasten that restoration. He showed his hand early when he supported Vice President Dick Cheney's refusal to name the participants in a committee studying energy policy. The war on terror provided further opportunities. By 2006, the president's end of the seesaw was at a post-World War II high. Now there is an opposite movement propelled, as before, by an unpopular war. With respect to both Vietnam and Iraq, Congress did not assert itself until corrective action became prohibitively difficult.

The principal lesson we can learn from the Iraq dilemma is that Congress should join the struggle with the president earlier in the development of a problem. It should combat the natural tendency to let the president take the lead in foreign crises.

The framers were under no delusion that the structure they built would keep the US out of foreign trouble. They had a more modest objective: to make foreign trouble less likely. There is no way we can change the Constitution to make it foolproof. The most we can do is to ensure that the people we choose to operate our government are skeptical and distrustful of each other.

• Pat M. Holt is former chief of staff of the Senate Foreign Relations Committee.