It was only a matter of time. Jon Huntsman, the former Utah governor and Obama administration official, has probably known for a long while that he would not be the Republican presidential nominee, at least not this year. It was only 10 days ago when Huntsman said he looks forward to the re-emergence of “a sane Republican Party based on real ideas.”

As a rule, candidates who believe their own party isn’t sane don’t win.

And sure enough, Huntsman, with no prospects of success, no fundraising, and a fleeing staff, has decided to call it a day.

Jon M. Huntsman Jr. will announce Monday that he is ending his bid for the Republican presidential nomination and endorsing Mitt Romney, narrowing the field and erasing a challenge to Mr. Romney from the moderate wing of his party.

Mr. Huntsman, who had hoped to use the South Carolina primary this week to revive his flagging candidacy, informed his advisers on Sunday that he was bowing to political reality and would back Mr. Romney, whom he accused a week ago of putting party ahead of country.

The timing of Huntsman’s departure is a little odd. There’s a debate tonight, which he’d already agreed to participate in, and over the weekend, Huntsman picked up the endorsement of South Carolina’s largest and most influential newspaper.

But the reality of the situation apparently wouldn’t budge. Huntsman put all of his eggs in one basket — betting everything on a strong showing in New Hampshire last week — and failed. There was simply no point in delaying the inevitable any further.

There is a certain irony to Huntsman’s meager showing: he was always the candidate Democrats feared most. Obama’s re-election team saw Huntsman as a very credible general-election candidate, with broad ideological appeal. It turns out, the guy just couldn’t get his own party to take him seriously.

Huntsman did, however, win over one enthusiastic constituency: the political media, which adored him to such an embarrassing degree, I’ve been surprised editors resisted the urge to draw little hearts around pictures of Huntsman before publication. Never before has a no-shot candidate, generating low-single-digit support in national polls, been the subject of such media attention and adulation. Unfortunately for him, that didn’t translate into a lot of votes.

What rankles this morning, though, is Huntsman’s immediate endorsement of Romney. Because they’ve competed for a similar intra-GOP contingent, Huntsman has been relentless in going after the frontrunner, as aggressively as anyone in either party. Less than a week ago, Huntsman told reporters that Romney “enjoys firing people; I enjoy creating jobs.” He added that Romney is “completely unelectable.”

And that’s just last week. In 2011, Huntsman and his campaign called Romney’s record on job creation “abysmal by every standard.” The campaign also put together a series of brutal web videos, attacking Romney on flip-flopping — all of which were quietly purged last night.

In any case, Huntsman didn’t necessarily embarrass himself in the race, and if President Obama wins re-election, the former governor will be fairly well positioned to give this another try in 2016, which may very well have been the point of this exercise in the first place.

As for the short-term impact, Huntsman’s support is pretty weak, but his supporters are likely to migrate to Romney, making it that much more likely that the frontrunner will continue to cruise towards the Republican nomination.

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Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.