Mitt Romney addresses the crowd as New Jersey Gov. Chris Christie listens at Ariel Corporation on Oct. 10, 2012, in Mount Vernon, Ohio. (Jamie Sabau/Getty Images)

Fortunes change quickly in politics. Three months ago, Chris Christie was on the Republican mountaintop, and Mitt Romney was in the valley. Today, Christie’s once-bright future is clouded by scandal, and, wonder of wonders, Romney is enjoying a moment in the sun.

Christie’s downfall has come quickly. How permanently damaged he is, no one can say. The New Jersey governor faces investigations that are likely to turn up new, if not harmful, information. He has tumbled in the polls and his image has been turned upside down. His strengths have become perceived weaknesses. He is fighting back fiercely while trying to carry on normally.

Romney’s reemergence is equally unexpected. Virtually discarded by the GOP after his loss to President Obama, he is now the unlikely star of a well-reviewed Netflix documentary about his two unsuccessful presidential campaigns. He has taken the opportunity of its release to strut a bit in public. He has done morning television, Sunday talk, interviews with reporters and — with his wife, Ann — attended Super Bowl events.

The warmer Romney seen in the documentary has sparked surprising talk about a possible 2016 presidential run. Romney has been firm in his rejection every time the subject has been mentioned. Still, the chatter continues.

The encouragement, which has gone directly to some of those around Romney, comes from two places. The first is from Republican donors, who know the table stakes necessary for a successful campaign in 2016. Romney and Obama each raised about $1 billion in 2012. The next campaign isn’t likely to be any less expensive.

The Bridge-gate scandal could hurt New Jersey Gov. Chris Christie, as the political blame-game intensifies and new allegations come to light. PostTV takes you through the story, from beginning to now. (Julie Percha/The Washington Post)

Republican donors look at the Democrats and see Hillary Rodham Clinton looming as the party’s possible nominee. They have no doubt that she could amass any amount of money necessary. Who can raise that much on the GOP side? It was assumed that Christie could. If there is a core constituency for his candidacy, it is among the wealthy, establishment, donor class of Republicans. Jeb Bush presumably could raise it. Few others are on the list.

Romney has done it once and probably could again. He’s personally worth north of $200 million, or was at the time of his last campaign. In 2008, he spent considerably from his own fortune. He needed to buy recognition. Last time, he got others to give. But personal money and the demonstrated ability to raise it elsewhere generate interest from those who have helped finance campaigns.

Donors, however, are famously skittish, often the first to wail at signs of trouble in a campaign. Although often closely watched, they are not always the most reliable of political barometers. If Christie weathers this episode, many will be back in his camp.

The second source of encouragement is coming from people who were impressed with the Romney they saw in the Netflix documentary — more human than the Romney who was given to gaffes on the campaign trail and who had trouble connecting with working people. Had that Romney been more visible in 2012, they believe, he might have won. Perhaps.

It is more than ironic that some of these donors, now worried about Christie, are thinking about a third Romney campaign. Some of them were looking to Christie because they were lukewarm toward the sometimes-awkward Romney. That was in the summer of 2011, when Romney was the front-runner for the GOP nomination but not fully loved by the party.

They saw in Christie what they couldn’t see in Romney: a tough, blunt, seemingly authentic leader who spoke directly, brooked no criticism without a fiery response, and was more than ready to bash the president as a weak leader.

Christie’s head was turned by the courtship, but nothing could change his mind that 2012 was not his time. When he finally, definitively said no, he quickly endorsed Romney. “Wow, Christmas in October,” an ecstatic Romney said, according to Christie’s retelling.

Yet enough other moments have occurred to feed the idea that tension always existed between Romney and Christie, or at least between those around Romney and those around Christie.

Early in 2011, Christie told Romney, who was eager to start raising money in New Jersey, to back off. Christie said he told Romney, “If you raise money in New Jersey in any kind of aggressive, organized way, it’s going to make it very unlikely that I’ll be able to support you.” It was, as Christie later told me, “a rather tense conversation.” Romney “left not very happy with the approach I took.”

Christie was on Romney’s short list of possible vice presidential candidates. Why he was scratched is a story only Romney can tell. They had a telephone conversation in July 2012 about a little-known Securities and Exchange Commission rule that makes it difficult for sitting governors to raise money in a presidential campaign from people in financial institutions.

The rule was an obstacle in Christie’s path to join the ticket (as it will be for any sitting governor who seeks the nomination in 2016). Romney wondered whether Christie would be willing to resign as governor to become his running mate. Christie laughed off the idea. They did not discuss the vice presidency until Romney told Christie he was picking someone else.

There also were complaints within Romney’s campaign — and more broadly within the party — about Christie’s keynote address at the Republican National Convention. The critics said Christie spent too much time talking about himself and not enough about Romney. Christie said he was stung by the criticism. He thought he had done the job Romney’s advisers wanted.

Then came Hurricane Sandy, which a week before the election devastated New Jersey and other parts of the Northeast. Christie offered effusive praise for Obama’s response, to the great consternation of many Republicans. He sent word to the Romney campaign not to ask him to appear at a pre-election rally. He would be focusing on his state and the recovery.

Some Republicans are still rankled by what Christie did that week, which is why there are suggestions that some of the people in Romney’s campaign have taken particular pleasure in seeing Christie brought down a few notches.

Not Romney, however. He has enjoyed a good relationship with Christie despite all, his advisers say. He has been staunch in his support of Christie since the scandal erupted, just as he defended Christie’s actions after the hurricane.

It’s likely that nothing serious will come from the talk of a third Romney presidential campaign. Romney is too sensible. But it may be enough for him to know that there even is such talk, after the criticism he and his team received after the defeat. That Christie’s problems, however, would somehow prompt a new look at the 2012 Republican nominee is one more strange twist in this unexpected turn of events.