CLEVELAND – After 10 minutes of ringing acceptance from the crowd at the Republican National Convention Wednesday, Texas Sen. Ted Cruz left the stage chased by thousands of angry boos as he failed to close with a ringing endorsement of Donald Trump.

On a night when Republicans promised a plan to “Make America First Again,” Cruz was one of three failed GOP presidential candidates who exchanged insults with Donald Trump for months but were tasked with touting the billionaire who knocked them off the campaign trail.

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But when it came right down to it, Wisconsin Gov. Scott Walker and Sens. Cruz (“Lyin’ Ted”) and Marco Rubio of Florida ( “Little Marco”) couldn’t quite bring themselves to do it.

Not ringingly, anyway.

Cruz, who spoke last of the three, missed an opportunity to look like a much bigger man than he came off and earn the love of the party’s base rather than its enmity. His attacks on Hillary Clinton were direct, but his support for Trump was thin enough to read a 2020 “Ted Cruz For President” poster through.

The byplay between Trump and Cruz on the campaign trail was astonishingly ugly. That’s what would have made a ringing endorsement so powerful and makes its absence so telling.

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Imagine if Cruz had said, “As heated as the battle between us got, I’ve gotten to know him better now and I believe he can be a much finer president than his opponent. And I have to put that above petty personal issues and ask you to fight with every fiber of your being to elect this man president.”

Instead Cruz called Trump’s name only once, which made it seem as if his stop on the stage was meant merely to deflect accusations of disloyalty to the GOP. And when the crowd turned on him toward the end of his remarks, bellowing “endorse Trump” and all but drowning him out, it left his future in the party as much in doubt as the sincerity of his support for the nominee.

Walker was the first of the three out of the race, and so took the least direct heat from Trump, but he also spent months flip-flopping on whether he’d support Trump. When he did ask the crowd to vote for Trump on stage Wednesday, he did so by arguing that to do anything else would be a vote for Hillary Clinton.

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Of the three, Rubio’s endorsement was the strongest. But it was also shockingly short and delivered via video, making it clear Rubio was only willing to do so much for the cause.

These three former rivals didn’t do Trump any damage Wednesday night. But they also did a lot less to convince the nation Trump is a great choice for president than they might have, and perhaps, needed to if Trump is to triumph.

And they did less for themselves with party voters than they might have in fighting for the GOP cause.