Speaker John Boehner (R-Ohio) has declined to comment on the case, saying he is waiting to talk to Grimm. The two Republicans haven’t spoken, according to a knowledgeable aide.

After a court appearance in Brooklyn earlier today, a defiant Grimm told reporters he had spoken to GOP leadership but had no intentions of voluntarily giving up his seat.

Like Boehner, other top House Republicans have ducked the Grimm scandal thus far. An aide to House Majority Leader Kevin McCarthy (R-Calif.) had no immediate comment Tuesday. A spokesman for House Majority Whip Steve Scalise (R-La.) said the No. 3 member of the Republican leadership had nothing to say.

Yet the situation will surely test the Republican leadership’s promise to hold members of Congress to the highest standards.

Boehner and his top lieutenants cannot stop Grimm from being sworn in for a third term on Jan. 6. But they can urge the House Ethics Committee - which has stood aside while the Justice Department investigated and prosecuted Grimm - to move quickly on a resolution to expel Grimm. The Ethics Committee has stood aside as the Justice Department worked its investigation.

However, if there was a good time to plead guilty to a federal crime, it is now. With the Christmas holiday around the corner, Washington has ground to a halt. The members of leadership and their top aides are spread out all over the country, not down the hall from each other in the Capitol.

Democrats, for their part, Democrats are already pouncing on the issue, using it as a cudgel to bash Boehner and other House Republicans. House Minority Leader Nancy Pelosi (D-Calif.) and the Democratic Congressional Campaign Committee are already calling on Boehner to publicly declare Grimm should step down. Another Democrat, Rep. Gerry Connolly (Va.), said on Twitter that Grimm should give up his seat on his own or be expelled from the House.

“Rep Michael Grimm is now a self-admitted felon. He must resign his seat in Congress or be expelled. No convicted felons in the House,” Connolly said on Twitter.

As for Grimm, the timing of his guilty plea is fortuitous. His insistence Tuesday that he will not resign comes right before Christmas and New Year’s Day. Congress doesn’t return to Washington until early next month.

Still, several sources in House Republican leadership do not believe that Grimm will be able to survive his admission that he broke federal law. Grimm says the alleged crime happened before he was a member of Congress, which is ringing hollow with many aides in leadership.

House Republicans can take several steps to isolate Grimm. Grimm has already given up his seat on the House Financial Services Committee, meaning he has no committee assignments. GOP leaders could move to expel him from the House Republican Conference, as Democrats did to the late Rep. Jim Traficant (Ohio) when he was convicted on federal corruption charges in 2002.

But short of expulsion, there is little that GOP leaders can do to Grimm, who easily won reelection in November. He can still vote, although House rules say that a member of the chamber who has been “convicted by a court of record for the commission of a crime for which a sentence of two or more years’ imprisonment may be imposed should refrain from participation in the business of each committee of which such individual is a member, and a member should refrain from voting on any question at a meeting of the House or of the Committee of the Whole House.” Federal sentencing guidelines provide for a 24 to 30 month sentence in a situation like that facing Grimm, although his attorneys will ask for a far lighter punishment.

Grimm’s viability as a member also depends on the patience of his staff. If his aides begin leaving en masse, he could be in trouble. He has already had trouble filling some staff slots, sources said.