Is Jeb Bush's campaign losing steam?

A small crowd came out for Bush’s first post-debate rally. How will the onetime GOP front runner convince voters he has the energy to win the nomination? 

Twenty-four hours after his debate performance in front of an audience of 23 million Wednesday night, Republican presidential candidate Jeb Bush appeared in front of a more humbling number: about 100.

As the Washington Post’s David Weigal and Ed O’Keefe reported, Mr. Bush’s first post-debate rally took place in a half-full Las Vegas rec center room.

Whether the former Florida governor’s campaign is losing its luster or focusing on the long game, his aides knew he had to show bravado during the GOP presidential debate on CNN.

And the change in attitude showed: he directly engaged Donald Trump and defended his record.

Recently, critics, including Mr. Trump, have described Bush’s calm demeanor as "low-energy." At the Las Vegas event, the candidate seemed to push back at this characterization, saying, “I hope that I am so brilliant and so eloquent and so high-energy that you feel compelled to caucus for me.”

But Bush has more to be concerned about than just energy. Currently, Washington-outsider candidates in the Republican field have gained serious traction. Besides Trump, who continues to dominate the polls, neurosurgeon Ben Carson and business executive Carly Fiorina are surging in polls and garnering headlines.

To confront this trend, Bush has branded himself as a Beltway outsider, despite his family name. He released a plan in July that would shrink the size of government and rein in the influence of lobbyists. As The New York Times’ Michael Barbaro reported,

“He proposed heightened levels of disclosure that would require members of Congress to use their websites to report every meeting with a lobbyist on a weekly basis. And his six-year ban on lobbying for United States lawmakers is far tougher than the current requirement: one year for members of the House, two for those in the Senate.

But as a candidate, Mr. Bush has harnessed the fund-raising prowess of the K Street crowd, bringing in hundreds of thousands of dollars for his campaign through Washington lobbyists, political operatives, lawyers and business leaders.”

This is part of a strategic effort to tap into the anti-Washington sentiment that voters identify with and other candidates are using to great effect.

But Bush may not have too much to worry about. Nate Silver, editor-in-chief of FiveThirtyEight.com and a statistician who has accurately forecast election outcomes in the past, told CNN’s Anderson Cooper that the chance of Trump or Carson winning the nomination is about 5 percent.

“If you look at the polling, a lot of times a candidate who is leading the polls now mid-September didn't win the nomination, didn't even come close. So if you look four years ago, Rick Perry was in the midst of a surge right now. [12] years ago on the democratic side, … Howard Dean was surging, Hillary Clinton was still away ahead of Barack Obama in 2008. Rudy Giuliani was leading the polls in 2008. I think people, there's so much interest in this election, in this campaign, people forget that polls five months before Iowa historically have told you very, very little.”

Other writers at FiveThirtyEight seem to think these candidates from outside the political establishment will eventually combust, leaving caucus-goers to choose a traditional candidate.

And while donors may be nervous over his shaky poll numbers, Bush has still raised more money than any other candidate.

With more than four months to go before the first primary, Bush may still have time to fine tune his presence on the campaign trail, placate the donors, and put the insurgency to rest.