THE BURNED OVER DISTRICT

And there is no greater proof of the Republican fear than the party leadership encouraging congressional incumbents to dump on Trump if they need a campaign boost.

Senior Republican Party leaders began urging their most imperiled incumbents on Wednesday to speak out about the wrongdoing surrounding President Trump, with Representative Tom Cole, a former House Republican campaign chairman, warning, “Where there’s smoke, and there’s a lot of smoke, there may well be fire.”

Democrats face their own pressure to shed their cautious midterm strategy and hammer the opposition for fostering what Democratic leaders are labeling “a culture of corruption” that starts at Mr. Trump and cascades through two indicted House Republicans to a series of smaller scandals breaking out in the party’s backbenches.

One day after Michael D. Cohen, the president’s former lawyer, implicated Mr. Trump in payoffs to two women before the 2016 election, and the former Trump campaign chairman Paul Manafort was convicted of eight felonies, Republicans were concerned that the worst may be to come in the House, although the party’s senators expressed few worries.

By urging some candidates to speak out or at least stay silent, Republican leaders who gravely fear losing control of the House risked opening the first significant rift between the Trump White House and the Republican-controlled Capitol.

“Anybody who says this is not disturbing is not being honest,” said Mr. Cole, an Oklahoman and the former head of the National Republican Congressional Committee, adding, “so my advice to any candidate would be: Keep your powder dry and don’t rush to attack or defend anybody because you just don’t know enough to have a reaction that you can still defend three months from now.”

On cue, Representative Carlos Curbelo, Republican of Florida, called the accumulation of Trump-related scandals a “sad chapter in our country’s politics” and said that “no one is above the law.” Mr. Curbelo, in a tough re-election fight, also reproached the president for his caustic attacks on the special counsel, Robert S. Mueller III.

“He’s making a major mistake by attacking the Mueller probe in such a personal way,” said Mr. Curbelo, who represents a district that Hillary Clinton won handily in 2016. “The best thing for everyone, especially if the White House is so confident that the president will be absolved in this process, is to let the process continue.”

Nearly as alarming to House Republicans were the mushrooming scandals in their own chamber, misdeeds that may dampen turnout among conservative voters.

Only hours after the convictions of Mr. Cohen and Mr. Manafort, Representative Duncan D. Hunter of California was indicted on a charge of using campaign money to fund a lavish lifestyle, including the alleged purchase of golf shorts masked as a charitable veterans contribution.

Those charges came only weeks after Representative Chris Collins of New York was arrested on charges of insider trading, something that has also tarnished a handful of his colleagues, including Representative John Culberson, an endangered Texas Republican. Mr. Collins and Mr. Hunter were Mr. Trump’s two earliest congressional supporters.

In Virginia, Representative Scott Taylor is accused of forging signatures to get an independent on the ballot this fall to help save his seat. And in Florida, Representative Vern Buchanan is accused of accepting a seven-figure yacht loan from a bank lobbying for last year’s tax cut, then purchasing the 73-foot vessel on the same day he voted for the measure he helped write.

“It has been a really bad August,” as Mr. Cole put it.

Mr. Hunter’s Democratic opponent, Ammar Campa-Najjar, released a video declaring, “The division, chaos and corruption in Washington has gone too far.”

It would appear that the Republicans have their nuts in a salad shooter right now. They are going to need all the gerrymandering, vote suppression, fraud and Russian hacking they can get to keep from being swamped in November.