Rep. Pete Sessions (R-Tex.) (Win McNamee/Getty Images)

To see just how far the once-odds-on favorite in the Republican presidential race has fallen, let's look back last year, when Rep. Pete Sessions (Tex.), a senior House Republican, endorsed Jeb Bush for president:

“What we’ve got to do is find someone who can rally us together,” said Sessions in an interview for Lone Star Politics. “Jeb Bush is my answer.”

At the time, Sessions said that Bush had some "frailties," such as that "he's a little anemic and he’s a little cautious," but overall he felt pretty good about Bush's chances.

Now, two days after Bush finished sixth in the Iowa caucuses, with less than 3 percent of the vote, Sessions appears on the verge of changing his mind:

"I’m en­dors­ing Jeb Bush. But that was 10 months ago. He has since then not sold him­self as well as he had wanted,” Sessions told National Journal's Daniel Newhauser and Alex Rogers. “Every­body is weigh­ing and bal­an­cing what they know now that they didn’t know 10 months ago, and I think that the per­son who gets closest to me is a [Marco] Ru­bio.”

Ouch. When your prominent endorsements start publicly reconsidering their options, you know things are bad.

Really, Sessions's comment and Bush's poor Iowa showing are just the latest, most visible examples of a candidate who has spent most of his time trying to stop his steady decline in the polls, often to no avail.

Backed by more than $100 million in fundraising in the first half of 2015, Bush first tried to woo voters with his record as governor of Florida in the 1990s and his policy expertise. He promised a "joyful" campaign.

But that was tough to do in the face of the Donald Trump tornado. Bush came across as wooden and awkward on debates and on the campaign trail. He pivoted between ducking Trump and attacking him head-on. Nothing seemed to work.

After a particularly disastrous October debate, when Bush's former protege, Sen. Marco Rubio (R-Fla.), owned Bush, The Fix's Chris Cillizza wrote that "it became clear that Bush was more than just rusty from having not run a campaign in more than a decade. He was simply underwhelming at every turn."

After the first votes have finally been cast in the presidential race, it seems at least one of Bush's prominent backers agrees.

[Will Jeb Bush win the Republican nomination?]