When fellow members of your state's congressional delegation say you should resign, your days are probably numbered -- especially when they are the highest-ranking member of your own party.

Sen. Kelly Ayotte (R-N.H.) said Monday that Rep. Frank Guinta (R-N.H.) should resign following revelations from the Federal Election Commission that he accepted more than $300,000 in illegal contributions from his parents.

Guinta said he put the money into his parents' accounts, which they gave back to him, and he loaned to his campaign. But the conservative New Hampshire Union Leader editorial page didn't buy it, publishing a short and to-the-point editorial calling him a liar.

Other Republicans in the state have showed their lack of confidence in Guinta, too, or at least haven't rushed to his defense. According to the Boston Globe, the state party hasn't said anything about this situation, and former Rep. Jeb Bradley, who Guinta once worked for, said the congressman is "on a pretty lonely island these days." New Hampshire Republicans have begun strategizing over phone calls about who should run in Guinta's place.

Ayotte's comments suggest the GOP establishment is firmly planning a post-Guinta world. Senators don't just call on congressmembers of their own party to step down unless it's untenable. And now, he'll have a harder time making the case he should keep his seat with Republicans calling for him to step down.

And even if he tries to stick it out, a 2016 reelection campaign would be a difficult proposition.