Republican presidential candidate Donald Trump said "the loser of the night was Marco Rubio" during his celebratory speech on Super Tuesday. "At least you can say that Ted has won something," the frontrunner said. (Video: Reuters/Photo: Jabin Botsford)

The window for stopping Donald Trump closed almost completely Tuesday night, leaving the demoralized anti-Trump forces with two weeks and no agreed-upon strategy for denying the New York billionaire the Republican presidential nomination.

Trump pulled out victories in seven of the 11 contests that made up the biggest single primary-caucus night of the nominating season. His remaining rivals — Sen. Ted Cruz of Texas, Sen. Marco Rubio of Florida and Ohio Gov. John Kasich — and their allies were left to cling to the flimsiest of hopes that a reversal of his fortunes still lies on the near horizon.

For Rubio, the hope of many in the establishment, Super Tuesday turned into a super disappointment. He made a run at Trump in Virginia but fell short. Late Tuesday, he was declared the winner in the Minnesota caucuses. Still, that left his win-loss record this year at 1-14. Meanwhile, he was running third in at least half the states, and in some of those states his percentage of the vote was low enough that he was in danger of winning few or no delegates.

Rubio has been described by many as the future of his party. His performance to date instead has reinforced his image as a politician who has not lived up to that potential. Were it not for the Washington suburbs in Northern Virginia, where a well-educated and government-connected electorate gave him support strong enough to place second, his bad day would have been even more dispiriting.

Despite five days of relentless attacks on Trump, which started at last week’s GOP debate in Houston and carried through a raucous weekend of campaigning, Rubio was not able to deliver significant results. He scored well among late-deciding voters; in Virginia they favored him over Trump by about 20 points. But there were not enough of them to overcome the hold Trump has on anti-establishment Republicans who remain in control of the nominating battle.

Cruz did more than enough to argue that he should become the main challenger to Trump, carrying his home state of Texas, as he had long predicted, as well as Alaska and Oklahoma. Along with his victory in the Iowa caucuses at the beginning of last month, he remained through much of Tuesday night the only Republican who could say he had defeated the party’s front-runner anywhere.

Months ago, Cruz envisioned that Super Tuesday, with its Southern flavor, would be the day he took command of the GOP nominating contest. Instead, it was the day he managed to preserve his candidacy, although he remains at a distinct disadvantage against Trump, particularly with Rubio and Kasich still in the race. Which was why he said Tuesday night that the only way to stop Trump is for the anti-Trump forces to get behind a Cruz candidacy.

Cruz can now claim, with more credibility, the mantle of the true conservative in a conservative party against a front-runner with no clear ideology and views at odds with GOP orthodoxy. But whether he is capable of taking down Trump in Northern states remains in question.

Kasich came in second behind Trump in tiny Vermont, but he, too, remains a distinct underdog as the campaign heads to Kansas, Kentucky, Louisiana and Maine on Saturday. None of those states looks hospitable to Kasich’s work-across-the-aisles message. He has pinned his hopes on next Tuesday’s Michigan primary and, crucially, the Ohio primary March 15.

For the GOP establishment, Super Tuesday had nightmarish qualities. Not only did Trump tighten his grip on the nomination, but the only candidate who has been able to beat him more than once so far is Cruz, the nemesis of Republican congressional leaders and what the Texas senator likes to call the “Washington cartel.” In a choice between Trump and Cruz, many who could be counted as part of that establishment would be hard-pressed to declare a preference.

What is remarkable is that the anti-Trump forces only recently awoke to the reality that Trump was on track to take the nomination. Instead, Trump has awakened a voting bloc that has soured on the party leadership. As he has continued to win, his support has continued to grow. In Georgia, Alabama and Massachusetts, he was winning with more than 40 percent of the vote.

For months, the party elite dismissed Trump, seeing him as a candidate who would burn himself out before the end of 2015. When he proved capable of surviving mistakes and misstatements that hurt most normal candidates, they then assumed that, when the primaries began, voters would reject him in favor of one of any number of establishment candidates who were then in the race.

Today, those desperate to prevent Trump from hijacking the party recognize his strength and his seeming inevitability but seem powerless to stop him.

Some believe that the most realistic scenario for stopping Trump begins with victories by Cruz, Kasich and Rubio in their home states. Cruz managed that Tuesday; Rubio and Kasich face those tests March 15. Theoretically, that could lock up enough delegates against Trump to prevent him from winning a majority before the Republican convention and force a battle in Cleveland in July for the nomination.

Another scenario calls for two of the three remaining viable candidates to quit the race, allowing the party to consolidate around a single remaining challenger. People have been talking about that for months. When he quit the race last year, Wisconsin Gov. Scott Walker said others should follow his lead in order to bring the anti-Trump forces together early enough to make a difference. What’s to say that will happen in time to make a difference in the trajectory of the race?

The fallacy of all this talk was underscored by former Utah governor Mike Leavitt.

“There’s this fallacy that some small group can get together and decide the outcome of this,” he said. “That does not exist. This is a marketplace of political ideas. The party is responsible for its structure but cannot dictate the outcome.”

Trump’s victories Tuesday seemed an echo of his win in South Carolina on Feb. 20. In the Palmetto State, he survived a debate in which he accused former president George W. Bush of lying about the existence of weapons of mass destruction as the pretext for invading Iraq and also praised Planned Parenthood for providing health-care services to millions of women.

On Tuesday, he survived not only the attacks from both Rubio and Cruz but also managed to win the majority of contests, despite a major controversy when he declined to denounce the Ku Klux Klan during an interview Sunday on CNN.

Trump predicted Tuesday night that establishment money will come pouring in against him over the next two weeks as he seeks knockout blows against Rubio in Florida and Kasich in Ohio. Up to now, that opposition has been scattered and inconsistent. They are loading up now for what could be one last effort to prevent something unimaginable to them when this campaign began.