House Democratic leader Nancy Pelosi downplayed Democratic interest of impeaching Brett Kavanaugh if the Supreme Court nominee is confirmed by the U.S. Senate.

"Let's take it one day at a time," she told the audience at the Atlantic Festival on Tuesday, "We're not about impeachment...we're not about dividing the country."

But as the FBI aims to complete its supplemental background check into the allegations of sexual misconduct made against Kavanaugh by the end of this week, and as Senate Majority Leader Mitch McConnell plans to hold a vote on the nominee in the coming days, others have started to think about additional congressional action.

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"If he is on the Supreme Court, and the Senate hasn't investigated, then the House will have to," House Judiciary Committee ranking member Jerry Nadler told ABC's "This Week," when asked whether he would investigate Kavanaugh further for possible impeachment. "We would have to investigate any credible allegations of perjury and other things that haven't been properly looked into before," said Nadler, who stands to chair the committee if Democrats take control of the House of Representatives next year.

Brian Fallon, executive director for the group Demand Justice, told the Atlantic last week that he was confident a Democratic-led Judiciary Committee "would seek to reopen investigations that Republicans during this process have refused to conduct."

While it is difficult and rare to impeach a Supreme Court justice -- it's only happened once before the history of the court -- it is possible. And if Kavanaugh is confirmed by the Senate this week, the fight over this nomination figures to continue on into the midterms and, perhaps, beyond.

Impeachment proceedings for a member of the high court follow a similar process as it would for a president: requiring a simple majority vote from the House and approval from two-thirds of the Senate. Article II Section Four states that "the President, Vice President and all civil Officers of the United States, shall be removed from Office on Impeachment for, and Conviction of, Treason, Bribery, or other high Crimes and Misdemeanors." And Article III Section One states that "the Judges, both of the supreme and inferior Courts, shall hold their offices during good behavior."

Democrats are expected to gain congressional seats through November's election, but even the most generous of estimates wouldn't give the party the numbers needed in the Senate to impeach a Supreme Court justice. Still, party leaders in the House could have the power to issue subpoenas, broaden the scope of the investigation into Kavanaugh, and call for additional testimony.

Such a course hasn't been taken since 1804, when the House of Representatives, with the encouragement of President Thomas Jefferson, impeached Supreme Court Justice Samuel Chase, a federalist appointed by George Washington, on the grounds that he exhibited a partisan bent in his decisions.

The final article of impeachment accused Chase of "continually promoting his political agenda on the bench, thereby 'tending to prostitute the high judicial character with which he was invested, to the low purpose of an electioneering partisan.'" The Senate, however, acquitted Chase in 1805. In his 1992 book on impeachment, Chief Justice William Rehnquist said the Chase proceedings helped to set a precedent that a justice's rulings from the bench could not be used as grounds for impeachment.

In 1969, Supreme Court Justice Abe Fortas resigned under the threat of impeachment, amid reports he accepted payments from a foundation run by a friend and former client under federal criminal investigation.

The House of Representatives has impeached only 15 lower court judges, and only eight were convicted by the Senate, according to analysis by the Brennan Center for Justice. The most recent example was in 2010, when the House moved to impeach Louisiana District Court Judge Thomas Porteous on charges of accepting bribes and committing perjury. And by a vote of 94-2, Porteous was removed from the bench by the Senate. The previous year, Texas District Court Judge Samuel Kent resigned his posted after being impeached by the House on charges of sexual assault, obstructing of justice, and making false and misleading statements.

Pelosi's comments then reflect both the high bar for and the potential political fallout for the party if it proceeds with impeachment. "House Democrats can talk about it all they want, but nothing is going to happen until they get 67 votes and I don't see that happening," says Jim Manley, an adviser to former Senate Democratic Leader Harry Reid. "This is actually the wrong thing for any Democrats to be talking about at this point. Keep your eyes on the prize, which are elections in November."