In the past four years there has been an abrupt reversal in Congress's approach to oversight.

During the Clinton administration, Congress spent millions of tax dollars probing alleged White House wrongdoing. There was no accusation too minor to explore, no demand on the administration too intrusive to make.

Republicans investigated whether the Clinton administration sold burial plots in Arlington National Cemetery for campaign contributions. They examined whether the White House doctored videotapes of coffees attended by President Clinton. They spent two years investigating who hired Craig Livingstone, the former director of the White House security office. And they looked at whether President Clinton designated coal-rich land in Utah as a national monument because political donors with Indonesian coal interests might benefit from reductions in U.S. coal production.

Committees requested and received communications between Clinton and his close advisers, notes of conversations between Clinton and a foreign head of state, internal e-mails from the office of the vice president, and more than 100 sets of FBI interview summaries. Dozens of top Clinton officials, including several White House chiefs of staff and White House counsels, testified before Congress. The Clinton administration provided to Congress more than a million pages of documents in response to investigative inquiries.

At one point the House even created a select committee to investigate whether the Clinton administration sold national security secrets to China, diverting attention from Osama bin Laden and other real threats facing our nation.

When President Clinton was in office, Congress exercised its oversight powers with no sense of proportionality. But oversight of the Bush administration has been even worse: With few exceptions, Congress has abdicated oversight responsibility altogether.

Republican Rep. Ray LaHood aptly characterized recent congressional oversight of the administration: "Our party controls the levers of government. We're not about to go out and look beneath a bunch of rocks to try to cause heartburn."

Republican leaders in Congress have refused to investigate who exposed covert CIA agent Valerie Plame, whose identity was leaked after her husband, Joe Wilson, challenged the administration's claims that Iraq sought nuclear weapons. They have held virtually no public hearings on the hundreds of misleading claims made by administration officials about Iraq's weapons of mass destruction and ties to al Qaeda.

They have failed to probe allegations that administration officials misled Congress about the costs of the Medicare prescription drug bill. And they have ignored the ethical lapses of administration officials, such as the senior Medicare official who negotiated future employment representing drug companies while drafting the prescription drug bill.

The House is even refusing to investigate the horrific Iraq prison abuses. One Republican chairman argued, "America's reputation has been dealt a serious blow around the world by the actions of a select few. The last thing our nation needs now is for others to enflame this hatred by providing fodder and sound bites for our enemies."

Compare the following: Republicans in the House took more than 140 hours of testimony to investigate whether the Clinton White House misused its holiday card database but less than five hours of testimony regarding how the Bush administration treated Iraqi detainees.

There is a simple but deplorable principle at work. In both the Clinton and Bush eras, oversight has been driven by raw partisanship. Congressional leaders have vacillated between the extremes of abusing their investigative powers and ignoring them, depending on the party affiliation of the president.

Our nation needs a more balanced approach. Congressional oversight is essential to our constitutional system of checks and balances. Excessive oversight distracts and diminishes the executive branch. But absence of oversight invites corruption and mistakes. The Founders correctly perceived that concentration of power leads to abuse of power if unchecked.

The congressional leadership is wrong to think that its current hands-off approach protects President Bush. In fact, it has backfired, causing even more harm than the overzealous pursuit of President Clinton. Lack of accountability has contributed to a series of phenomenal misjudgments that have damaged Bush, imperiled our international standing and saddled our nation with mounting debts.

Asking tough questions is never easy, especially if one party controls both Congress and the White House, but avoiding them is no answer. Evenhanded oversight is not unpatriotic; it's Congress's constitutional obligation.

The writer is a Democratic representative from California and ranking minority member of the principal House oversight committee.