They said this day would never come.
After months of floating above the fray in the Republican primaries, declining to challenge the frontrunner, and grandiosely celebrating second- and third-place finishes, Marco Rubio finally decided to join the ugly, messy brawl in Thursday night's presidential debate.
He didn't have much of a choice.
In the immediate wake of last week's South Carolina primary, the GOP rushed to crown Rubio as the establishment standard-bearer, giving him the mandate save the party from Donald Trump. But much to the chagrin of some impatient Republican opinion-makers and elites, Rubio initially showed little interest in attacking Trump — shrugging off reporters' questions about him, and directing his campaign to focus their firepower on Ted Cruz.
The calls for Rubio to get tough grew louder Tuesday when Trump tauntingly highlighted their apparent detente in a speech to supporters in Nevada. "I've been very nice to Rubio, because he hasn't hit me," Trump said. "When he does, you will see what happens."
On Thursday night, millions of debate-watchers did get to see — and it wasn't pretty for The Donald.
Indeed, the first half of the debate was dominated by Rubio's tussles with Trump, as the senator energetically recited what seemed like an entire opposition research file and the billionaire responded with his trademark tough-guy rejoinders. Neither candidate emerged un-bruised from these skirmishes, but Rubio employed a tactic that few of Trump's adversaries have used until now. Rather than allowing space for Trump's comebacks to land and draw laughter or applause, the senator routinely stepped on his opponent's punchlines.
This, combined with Trump's penchant for interruptions, resulted in an awful lot of inaudible crosstalk.
Take, for example, this selection from the transcript of Thursday's debate. Rubio had just accused Trump of being "the only person that has ever been fined for hiring people to work on your projects illegally."
TRUMP: No, no, I'm the only one on the stage that's hired people. You haven't hired anybody.
(APPLAUSE)
RUBIO: In fact, some of the people...
(CROSSTALK)
TRUMP: And by the way, I've hired -- and by the way, I've hired tens of thousands of people over at my job. You've hired nobody.
RUBIO: Yes, you've hired a thousand from another country...
TRUMP: You've had nothing but problems with your credit cards, et cetera. So don't tell me about that.
RUBIO: Let me just say -- let me finish the statement. This is important.
TRUMP: You haven't hired one person, you liar.
RUBIO: He hired workers from Poland. And he had to pay a million dollars or so in a judgment from...
TRUMP: That's wrong. That's wrong. Totally wrong.
RUBIO: That's a fact. People can look it up. I'm sure people are Googling it right now. Look it up. "Trump Polish workers," you'll see a million dollars for hiring illegal workers on one of his projects. He did it.
(APPLAUSE)
RUBIO: That happened.
TRUMP: I've hired tens of thousands of people over my lifetime. Tens of thousands...
RUBIO: Many from other countries instead of hiring Americans.
TRUMP: Be quiet. Just be quiet.
Trump's riposte about how Rubio had "never hired anybody" was his most devastating of the night, but because Rubio charged forward undeterred with his line of attack, it harder for Trump's point-scoring to sink in. By the end of the exchange, it sounded like little more than a disjointed jumble of shouting — but it was Trump and Rubio shouting at each other, and that's an image the latter's campaign hopes will stick in voters' minds come Super Tuesday.
"What tonight showed is that Marco is best equipped to take the fight aggressively to Donald Trump," said Rubio adviser Todd Harris in the post-debate spin room. "This is something that Sen. Cruz has been trying to do unsuccessfully for months now, and Marco showed tonight why this really is a two-person race."
Team Rubio sent out a fundraising email to supporters just after midnight in which campaign manager Terry Sullivan proclaimed that his candidate "brought it tonight."
"Everyone who watched tonight’s debate just saw who can stop Donald Trump, and beat the Democrats next fall," Sullivan wrote. "It's Marco. There is now no doubt."
While Cruz and Trump traded jabs as well, it was Rubio who landed the strongest blows of the night. During a round of questions about how to replace Obamacare, Rubio repeatedly — and aggressively — challenged the billionaire to provide detail to his health care proposal. The best Trump could muster under pressure was variations on, "We're going to have many different plans."
And in one of the most memorable attacks of the night, Rubio dismissed his business success as a mere byproduct of a rich father.
"If he hadn't inherited $200 million, you know where Donald Trump would be right now? Selling watches in Manhattan," he said.
The line drew loud applause in the debate hall and blew up Twitter, but it almost certainly got under Trump's skin more than any other unkind word said about him Thursday night. The real test for Rubio will be whether he can accelerate his campaign's momentum in Super Tuesday states amid a barrage of insults from The Donald in coming days.
In post-debate Trump was already making the Florida senator his new target for ridicule — and the Rubio campaign is geared up for the fight.
"I think you can certainly expect to see more of a contrast with Donald Trump in the coming days," said Harris.
Rosie Gray contributed reporting from Houston.