What are the signs that a candidate is about to quit the race for president?

1) He holds an "emergency" meeting with top advisors at home base.

In Houston, former Presidents George W. Bush and George H.W. Bush—and former First Lady Barbara Bush—will huddle with the third Bush family member seeking to ascend to the presidency, Jeb.

2) He radically cut staff because he's running out of money.

“The campaign is removing some senior staff from the payroll, parting ways with some consultants, and downsizing its Miami headquarters to save more than $1 million per month and cut payroll by 40 percent this week, according to Bush campaign officials who requested anonymity to speak about internal changes,” Bloomberg’s Mark Halperin and Michael Bender reported:

3) He cuts fundraisers because no one will donate.

The campaign also will cut travel expenses by 20 percent and overhaul Bush's schedule, shifting focus from fundraising events to make space on the candidate's calendar for more town hall meetings and other retail campaign stops in the early voting states.

In polls, Bush is at only about 7% nationally, behind Marco Rubio and way behind Donald Trump.  He's at 6% in Iowa, way behind Trump but also behind Rubio.  Bush is about 9% in New Hampshire, tied with Rubo and again way behind Trump.

The key detail isn't merely how far behind Trump he is; it's that he's also behind Rubio.  Even in his home state of Florida he is running fourth, once again behind Rubio.

There is nothing really that can be fixed with his campaign; the problem is the candidate.  And the big-money Chamber of Commerce interests would be equally happy with Marco Rubio.  Since he's ahead of Bush, there is no reason for Bush to be in the race.  Bush is running out of money for his campaign, but theoretically, he has big super-PACs supporting him.  I imagine they would easily switch to other Chamber of Commerce-approved candidates if Bush doesn't make progress soon.

His retreat for an emergency meeting of the Bushes looks like a last-ditch effort to retool, when there's nothing that can be fixed.  If Rubio continues to outpace him, how much longer can Bush last?

This article was written by Ed Straker, senior writer of NewsMachete.com, the conservative news site.