Herman Cain shot into the national spotlight by winning the first GOP presidential debate.  He continued to generate excitement with his Tea Party rhetoric and commitment to conservative social issues. 

Now, however, his campaign may be falling apart.

First of all, Cain's not raising enough money.  Not even close.

For the second quarter of 2011, he only raised $2.5 million.  This compares to $4.1 million for Jon Huntsman, $4.2 million for Tim Pawlenty, $4.5 million for Ron Paul, and between $15 to $20 million for Mitt Romney.

Back in the second quarter of 2007, John McCain took in $11.2 million, which was a bad quarter for him.  Meanwhile, Barack Obama raised $32 million and Hillary Clinton raised $27 million for that period. 

Of course, Cain can conceivably stage some kind of John McCain-like comeback later in the year.  However, that's less likely now that key staffers abandoned him, perhaps rendering him closer the fate of Newt Gingrich.

The first key staffer to leave him was Matt Murphy, his sole campaigner in New Hampshire.  Murphy left because he thought Cain should have invested more money into the New Hampshire strategy, according to the Union Leader publication.

Then, Tina Goff, Cain's Iowa organizational director, also quit.  The Iowa Republican reported that she quit because the Cain campaign refused to make a serious effort in Iowa.

Two other key staffers to quit Cain's campaign include Kevin Hall, Cain's Straw Poll coordinator, and Jim Zeiler, one of his regional campaign directors.