Ted Cruz and Republican presidential nominee Donald Trump started the 2016 presidential primary fast friends — but their political alliance quickly descended into a fierce rivalry.

Cruz’s supporters have spent the Republican National Convention attempting a coup designed to give Cruz the nomination, and trying to force through rules changes for Cruz’s long-term benefit.

Now, with Cruz set to deliver a speech today, some are left wondering — will Cruz put aside his own political ambitions, heed calls for party unity, and formally endorse Trump on the big stage?

Not likely, according to political experts, who have hinted that Cruz may instead have a last-minute ambush planned to embarrass Trump in front of a national audience.

The conservative senator repeatedly clashed with Trump during a bitter primary fight, with the New York billionaire repeatedly mocking the lawmaker as “Lyin’ Ted.”

If rumors are true, Cruz has his own mockery planned.

With an eye toward 2020, early reports indicate that Cruz’s team drafted his convention speech to focus on adherence to the Constitution, with some political backhands at Trump thrown in.

Cruz has not endorsed Trump despite pleas for party unity from the campaign and party officials. Nor is he expected to in his speech, the senator’s aides admit.

And Cruz’s refusal to endorse Trump will be the biggest story line to come out of Cruz’s speech, no matter what else he says.

Cruz only seems interested in setting himself up for another future run at president.

Paul Manafort, Trump’s top campaign adviser, said Wednesday that he expects Cruz to address “the same kind of issues he talked about in the primaries,” adding that his message will be “consistent with what Mr. Trump is talking about.”

Manafort’s words, however, suggested that relations between the two camps remain chilly.

Before Trump even accepts the nomination, Cruz’s supporters as well as critics say undercurrents in Cleveland are emboldening the senator’s band of believers and stoking his 2020 prospects, should Trump lose in November.

So what Cruz says Wednesday during his prime-time convention speech will be closely watched for clues about his presidential aspirations.

Cruz halted his campaign two months ago, having outlasted all but Trump in a field that once numbered 17 candidates. He finished a distant second in the delegate accumulation during the Republican nominating campaign.

His supporters clung to hope that that the convention would adopt rules that would free delegates to disregard the results of state contests and swing behind Cruz at the 11th hour. That hope was quickly dashed in opening-day proceedings.

Easily spotted in their cowboy hats and Lone Star flag shirts, dozens of Texas delegates shouted their objection when the push to change the rules was declared defeated in a voice vote that sounded close to those in the hall. An effort to have the vote recorded also failed, leaving anti-Trump Republicans feeling mistreated.

“There isn’t a Band-Aid big enough” to heal the hurt that erupted Monday, said Cruz supporter Ivette Lozano of Dallas. But she seemingly admitted she and other Cruz supporters were looking ahead to a Trump defeat.

“The plan is 2020, and we have an opportunity to do that,” said Lozano, a family practice physician.

Besides his prime-time speech, Cruz plans to hold a delegate appreciation event Wednesday, and address the Texas delegation Thursday.

Ron Kaufman, a Republican national committeeman from Massachusetts, said the flare-up over rules was choreographed to demonstrate public support for Cruz and preserve his future. “These votes had nothing to do with Trump,” he said. “This is all about Ted Cruz trying to make the party smaller.”

By smaller, he meant that Cruz supporters were pushing for primaries where only registered Republicans can participate. Cruz was more successful in such contests than in ones also open to voters who aren’t registered Republicans.

Cruz’s closest aides appear to be anticipating another run, considering how they are staying in his immediate orbit.

Former campaign manager Jeff Roe and data guru Chris Wilson formed a firm in part to provide a home for the expansive Republican database the campaign built over the last year. Senior campaign strategist David Polyasnky has been named chief of staff to Cruz’s Senate office.

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