Newlyweds Donald Trump Sr. and Melania Trump with Hillary Rodham Clinton and Bill Clinton on Jan. 22, 2005, in Palm Beach, Fla.

It sounds like something from “House of Cards”: Politician A enters into a secret alliance with Politician B — a loose-tongued rival from another party with the chutzpah, the cash and the power to play the spoiler — to ensure Politician A’s election.

Now, anyone living inside the Beltway can testify that Washington isn’t organized enough to work that way. But after GOP presidential front-runner Donald Trump said he would deny Muslims entry to the United States — and, faced with the condemnation of Republicans in Congress, indicated he might be considering running as an independent, a move that could elect a Democrat — one of Trump’s rivals tweeted out the Grand Trump-Clinton Conspiracy Theory.

“Maybe Donald negotiated a deal with his buddy @HillaryClinton,” Jeb Bush tweeted. “Continuing this path will put her in the White House.”

Bush’s comment came in response to a tweet from Trump Tuesday afternoon. “A new poll indicates that 68% of my supporters would vote for me if I departed the GOP & ran as an independent,” Trump tweeted — despite making a more-or-less meaningless pledge in September to refrain from doing just that.

There’s no doubt that Trump is a hand grenade launched into the middle of a crowded Republican field — one whose controversial comments about Muslims, immigrants and women, among many other subjects, have proven popular with the party’s base even as the Donald’s rivals try to distance themselves from them. But is his refusal to flame out really the result of high-level machinations among Trump, a former president and the Democratic presidential front-runner — a former first lady, U.S. senator, and secretary of state?

Probably not — but it sure is fun to speculate about it, as many have in recent months. Here’s a look at the “evidence”:

Trump used to be a Democrat.

Politicians switch parties all of the time. Ronald Reagan, to choose but one prominent example, was a Democrat until 1962. That didn’t stop him from defining conservativism and the Republican Party as we know it today.

But though Democrats sometimes become Republicans, none has proven as potentially destructive to the GOP as Trump. He’s not just a RINO, some say — he’s a RINO on a rampage.

“According to voting records, Trump is currently registered as a Republican, but in the past has been registered (and repeatedly voted) as a Democrat,” Gawker explained in August. “In fact, he appears to have switched between the two parties at least three times in the past 14 years: In 2001, he switched from Democrat to Republican; in 2008, he re-registered as Democrat; in 2010, he re-registered as a Republican (and maintained that affiliation through 2013). So Trump is certainly a Republican, but only in the sense that any voter can register as a Republican; it’s not like party officials perform an ideological litmus tests on mere voters.”

As Trump himself said in 1999: “I’ve actually been an activist Democrat and Republican.  I support almost equally — I really support people.”

In 2005, the Clintons attended Trump’s wedding.

Trump’s candidacy isn’t just suspicious to some because he once belonged to the Clintons’ political party. It’s suspicious because he’s the Clinton’s pal — golfing with Bill and, in 2005, hosting the Clintons at his wedding to Melania Trump. It was an invitation that Clinton had to explain away after Trump announced his candidacy earlier this year.

“I happened to be planning to be in Florida and I thought it would be fun to go to his wedding because it is always entertaining,” Clinton said. “Now that he is running for president it is a little more troubling.” She added: “I didn’t know him that well.”

Trump, meanwhile, implied that when he said “jump,” Clinton asked “How high?”

“Hillary Clinton, I said be at my wedding, and she came to my wedding,” he said in August. “She had no choice because I gave to a foundation.”

Trump donated to the Clinton Foundation.

Republicans love a good Clinton scandal, and went on the attack when some donations to the Clinton Foundation, allegedly given by people in need of political favors, were questioned earlier this year. Trump was right there down in front.

“If this was a Republican sitting right there, this would absolutely be considered illegal,” he said. He added: “This is about jail time; this isn’t about the voters.”

Yet, in one of the unabashed contradictions for which he is known, Trump gave at least $105,000 to the Clinton Foundation. At the first Republican presidential debate, Sen. Rand Paul (Ky.) asked him how he could criticize a charity he himself donated to.

“You’ve donated to several Democratic candidates. You explained away those donations saying you did that to get business-related affairs,” Paul said. “And you said recently, quote, ‘When you give, they do whatever the hell you want them to do.’”

“You better believe it,” Trump responded.

The mysterious Trump-Clinton phone call.

Donations are one thing. A personal phone call between Trump and former president Clinton just weeks before Trump declared his candidacy is, perhaps, something else.

Bill Clinton and Trump chatted in late May, as The Washington Post reported; the Donald became a candidate in mid-June. So what were Trump and President No. 42 discussing? Might it be a plot, years in the making, to ensure that Hillary doesn’t face a challenge from a more level-headed, moderate Republican — like Jeb Bush — who may have a better chance of winning a general election?

“The tone of the call was informal, and Clinton never urged Trump to run, the four people said,” Robert Costa and Anne Gearan reported, summarizing the comments of “four Trump allies.” “Rather, they said, Clinton sounded curious about Trump’s moves toward a presidential bid and told Trump that he was striking a chord with frustrated conservatives and was a rising force on the right.”

“Sounded curious,” eh? That’s pretty curious in itself.

Faced with this parade — or, at least, faint trail — of circumstantial evidence, some can only conclude that Trump and the Clintons are in it to win it together — by getting Trump to lose it.

“Donald Trump is a false-flag candidate,” conservative blogger Justin Raimondo wrote in July. “It’s all an act, one that benefits his good friend Hillary Clinton and the Democratic party that, until recently, counted the reality show star among its adherents. Indeed, Trump’s pronouncements – the open racism, the demagogic appeals, the faux-populist rhetoric – sound like something out of a Democratic political consultant’s imagination, a caricature of conservatism as performed by a master actor.”

Of course, this would mean that the Clintons — who, for all of their political power, couldn’t beat Sen. Barack Obama (Ill.) in the 2008 Democratic primary — would have had to cultivate a fickle, volatile real-estate developer turned reality TV host for more than a decade; bet that he could mount a serious presidential campaign, but one not serious enough to win a general election; and engineer this grand conspiracy without anyone finding out about it. Also, what would be in it for Trump — isn’t he already worth “10 BILLION DOLLARS“?

Then again, there may not be much difference between Trump sincerely trying to win and Trump tanking on Hillary’s behalf.

As conservative writer Allen Ginzburg put it in July: “If Trump had an agreement with Hillary to ensure her win by embarrassing R’s & then running as an indie, what would he be doing differently?”