Rep. Tom DeLay’s decision to bow to reality and surrender his House leadership cleared the way for Republicans to install a new leader. What they do will show whether they’ve gotten the message or are proceeding with business as usual.

It’s also clear that the House GOP isn’t the only congressional party that needs a leadership shake-up. There’s a good case that both parties in both houses would benefit from a new look at the top.

The current lineup seems a far cry from the days of such giants as Sens. Mike Mansfield and Bob Dole or Speakers Sam Rayburn and Thomas “Tip” O’Neill.

The events that prompted DeLay’s departure began when he ran afoul of House ethics rules. His departure was ensured when Travis County Dist. Atty. Ronnie Earle won indictments on charges stemming from the Republican’s role in raising funds for the 2002 elections.

The indictment, derided by many Republicans as partisan, triggered a GOP rule that an indicted party leader had to step down. DeLay’s allies tried last year to lift the rule, but bowed to pressure from other Republicans.

The underlying problem, though, stems from the political machine DeLay and his colleagues built with allies in Washington’s lobbying community. It produced a torrent of campaign contributions but also apparently led to potentially criminal misuses of their congressional power.

Individuals implicated in misdeeds by lobbyist Jack Abramoff, a key figure in the GOP machine, will ultimately face their own legal issues. But ties between the operation and the current House leadership require more than merely replacing one person.

After all, Majority Whip Roy Blunt of Missouri, the top candidate to replace DeLay, also was involved in the K Street Project, as was rival John Boehner of Ohio, though there is no evidence at this point that either did anything illegal. Speaker Dennis Hastert was DeLay’s deputy before the Texas Republican helped install him as speaker in 1998.

If Republicans are serious about changing their public image, they’ll opt for a clean sweep of their leadership.

The reasons for changing other congressional leaders have more to do with political ineptitude.

Sen. Bill Frist of Tennessee, who became Senate GOP leader after a flap over controversial comments by Sen. Trent Lott, has proved to be the weakest majority leader of modern times. He’s shown poor judgment on issues ranging from the Terri Schiavo case to his repeated threats to change the Senate’s historic filibuster rules, and his leadership has been complicated by his presidential ambitions.

Fortunately for his party and the Senate, Frist isn’t seeking re-election, one of the few members who made a two-term promise and kept it. His likely successor, Sen. Mitch McConnell of Kentucky, is far more adept and familiar with the way the Senate works.

Democratic leaders, meanwhile, have had some success in blocking presidential initiatives. Senate leader Harry Reid of Nevada used President Bush’s misstep in pushing private Social Security accounts to create the unity that killed the idea.

In the House, Rep. Nancy Pelosi of California has usually been able to minimize Democratic defections, making it harder for Republicans to pass bills as more of their members threatened to stray. However, the absence of six Democrats undercut her bid to beat a key budget measure.

But neither Reid nor Pelosi is a very effective public face for the party out of power. And neither has yet presented a positive agenda for next fall’s elections. Assailing the GOP’s “culture of corruption” and its handling of Iraq will only go so far.

In addition, Pelosi joined Democrats calling for total U.S. withdrawal from Iraq, a position that pleases party liberals, but the country as a whole rejects. It underscores the caricature of her as a “San Francisco liberal.”

And Reid weakened his position by refusing to return contributions from Abramoff’s lobbying associates and tribal clients. While he may have done nothing wrong, he’d be better to avoid any appearance of impropriety.

On Capitol Hill, parties don’t change leaders until they have to. That’s why the House Republicans alone are going to have a new election. But that doesn’t mean they’re the only ones who could benefit from new leadership.