The exceedingly strange endeavor known as Herman Cain’s presidential campaign appears to be inching closer to an end.

Businessman Herman Cain told senior members of his campaign that he is reassessing whether or not to remain in the Republican presidential race on a conference call this morning.

One adviser said that Cain will ponder his prospects over the next few days and will make a decision by the end of the week. Cain will keep his current campaign schedule.

It’s worth noting that Cain admitted in September that he’d considered dropping out of the race, but changed his mind after winning the “Presidency 5” straw poll in Florida. Apparently, when it looked like he had a reason to stick around, Cain was willing to keep his campaign going.

Two months later, Cain’s support is evaporating, and he’s now forced to deal with revelations he may have had a lengthy adulterous affair, which he only ended shortly before kicking off his campaign. His path to the GOP nomination is increasingly hard to see, so it stands to reason Cain might be eyeing the exits.

The Cain campaign has already conceded that the candidate is, in fact, “reassessing” whether or not to drop out. When TPM contacted campaign spokesperson J.D. Gordon for a comment on the state of Cain’s candidacy, Gordon’s full statement read, “We’re moving forward.”

At least for now, that is.

Remember, once talk of a withdrawal starts, it’s very difficult to make it stop. Every question from every reporter will be more or less the same: when will Cain drop out? Even if the candidate were to shift gears and recommit to the race, the campaign is likely to fall into a spiral — donors don’t want to write checks for a candidate who may not be in the race much longer; activists don’t want to volunteer for a campaign that’s nearing its end; etc.

Tick, tock.

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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.