Editor's note: With their party back in power for the first time since 1994, some senior House Democrats who will be rising to committee chairmanships are already planning to conduct investigations into wrongdoings of the Bush administration in everything thing from fraud and abuse in Iraq War contracting to illegal domestic surveillance and detainee interrogations. Incoming House Speaker Nancy Pelosi and other party leaders, however, are signaling that any investigations will be kept on a tight leash. They fear that scrutiny of the administration will make Democrats appear excessively partisan and cost the party votes in 2008. As for the possible impeachment of President George W. Bush, Pelosi has explicitly declared it to be "off the table."

Attorney Elizabeth Holtzman is one wise legal thinker who says that, whether or not it would be a political liability for the Democrats, impeaching Bush is their constitutional duty. Holtzman served four terms in Congress, where she played a key role in House impeachment proceedings against President Richard Nixon. Holtzman's full brief on this subject can be found in The Impeachment of George W. Bush: A Practical Guide for Concerned Citizens (Nation Books), which she co-wrote with Cynthia L. Cooper.

mpeachment is an essential tool for preserving democracy. The framers of our Constitution, determined to provide protections against grave abuses of power by a president, created the impeachment process as a special procedure for citizens. Through their representatives, citizens would be able to remove a president run amok.

Our founders created a new form of government that was designed to preserve liberty by breaking up power among three co-equal branches of government and instituting a system of checks and balances. But they worried deeply about presidential misconduct. Left unchallenged, it could be "fatal to the Republic," said James Madison. The new democracy needed the ability to remove a president, if necessary.

Impeachment is the first step of a two-step process that can result in the removal of a president from office. The House of Representatives first decides whether to charge the president with impeachable offenses. If a majority of the House votes to impeach, articles of impeachment, which contain the charges, are forwarded to the Senate. The Chief Justice of the Supreme Court presides over a trial in the Senate, and if two-thirds of the senators vote for conviction, the president is removed from office.

THE FOUNDERS SET A HIGH BAR—The grounds for removal of a president are stated in the Constitution in a phrase of only eight words: "treason, bribery and other high crimes and misdemeanors." Understanding the meaning of this spare language is helped by looking at the original debates on the Constitution. In adopting the impeachment provision, the framers identified treason and bribery as two key reasons for the removal of a president. Treason was defined in the Constitution as providing "aid and comfort" to enemies or "levying war" against the United States. Bribery is a well-established concept that hasn't changed much over time.

But the framers believed that these grounds were not sufficient. A president should also be removed for other "great and dangerous offenses" or the "attempts to subvert the Constitution," in the words of George Mason, a delegate from Virginia to the Constitutional Convention. The grounds were expanded to include "high crimes and misdemeanors"—an archaic phrase that the framers borrowed from British terminology dating back to the fourteenth century. It was defined as "an injury to the state or system of government."

Alexander Hamilton explained in No. 65 of the Federalist Papers that impeachment reached "those offences which proceed from the misconduct of public men or, in other words, from the abuse or violation of some public trust. They are of a nature which may . . . be denominated POLITICAL, as they relate chiefly to injuries done immediately to society itself." In essence, "high crimes and misdemeanors" describe a political crime, a serious and grave abuse of power or an abuse of public trust.

High crimes and misdemeanors are not limited to actual crimes. We debated this in the Judiciary Committee during Watergate and reached a firm conclusion. While commission of a crime may be grounds for impeachment, the phrase also covers conduct that is not a violation of the criminal code.

The key is whether the conduct is a grave abuse of power or a subversion of the Constitution. Some presidential misdeeds we encountered in the Nixon impeachment had a basis in the criminal law; others did not. On the flip side, not all violations of the criminal code are political crimes that rise to the standard of high crimes and misdemeanors.