The Question for Republicans After South Carolina: Can Anyone Stop Trump?

The current state of the race for the Republican presidential nomination was encapsulated by a conversation overheard last night in the lobby of the Marriott hotel in Columbia, South Carolina.

"We now refer to time as B.T. and A.T.," said a man explaining American politics to two British friends. "Before Trump and After Trump."

The outcome of the Republican primary last night in South Carolina confirmed that the A.T. era isn't likely to end anytime soon. Trump easily won the contest with 33 percent of the vote, ahead of Marco Rubio and Ted Cruz, who were virtually tied for second with 22.5 and 22.3 percent of the vote, respectively.

"It's an incredible movement with incredible people," a victorious Trump said last night to a cheering crowd at his primary party in South Carolina. "[I've] been saying make America great again and it's going to be greater than ever before. That's the kind of potential we have — greater than ever before."

Trump's win in South Carolina is even more remarkable considering that it looked like he was actively trying to lose the state in the days leading up to the primary. In the past week, Trump blamed 9/11 on George W. Bush and criticized his administration's invasion of Iraq, in a state where the former president is a beloved figure and the military is revered. He then praised Planned Parenthood for doing "wonderful things," before picking a fight with, who else, the Pope.

Related: Pope Francis Says Donald Trump 'Is Not Christian' — Trump Calls Remark 'Disgraceful'

According to B.T. logic, that might not be the best way to win a state where nearly 75 percent of Republican voters are evangelical Christians. But we're in A.T. now, and Trump could somehow do all of this and still win with the highest margin from evangelicals, along with nearly every other sector of the Republican electorate.

After Trump's victory, Jeb Bush, who finished a distant fourth, announced that was dropping out of the race.

"The people of Iowa, New Hampshire and South Carolina have spoken," said a tearful Bush at his primary watch party in Columbia. "Tonight I am suspending my campaign."

The former governor of Florida was once seen as frontrunner in the 2016 election, with solid name recognition from the very beginning and more money than any other candidate. But he failed to crack the top three in any state that has voted so far, despite having two former presidents as a father and older brother.

Bush's exit now essentially makes the Republican race a three-way contest between Trump, Cruz, and Rubio, though Ben Carson and Ohio Governor John Kasich have yet to end their campaigns. Cruz won in Iowa, where he was carried by the state's evangelical base, but he has yet to prove whether he appeals to a more diverse electorate in states like Nevada and Ohio.

Watch the VICE News documentary America's Election 2016: Trump Carolina:

The biggest challenger to Trump right now is Rubio, who stands to benefit the most from Bush's departure. His strong showing last night was due in large part to his ability to sweep up many of the voters that Bush was counting on, including higher-educated, upper-class pragmatic Republicans who identified with the party's establishment, according to exit polls from the Washington Post. Rubio won 47 percent of voters who said a victory in the November general election is their top concern, although those people only made up 15 percent of the total voters. Rubio also nabbed 36 percent of voters who wanted a candidate with experience in politics.

These were the voters that Bush had tried — and failed — to represent. It didn't help Bush that earlier in the week Rubio landed some of the most sought-after endorsements in the state, including Senator Tim Scott and Governor Nikki Haley. That mattered to Rubio supporters: 45 percent of his voters said Haley's endorsement was important.

It didn't take long for Bush's backers to switch allegiance to Rubio. Nevada Senator Dean Heller, who had previously endorsed Bush, threw his support behind Rubio on Sunday morning and said he plans to campaign with him in Nevada ahead of the state's Republican caucus on Tuesday. The Huffington Post also reported today that Mitt Romney is planning to endorse Rubio, which is one of the highest-profile endorsements in the Republican race yet.

Related: 'Dirty Tricks' in South Carolina: Pro-Cruz Robocall Hits Trump Over Confederate Flag

Even with the GOP base rallying around Rubio, there's a big question that still remains: Can he take on the unstoppable force that is Trump? Rubio and his allies certainly seem to be gearing up for the challenge. Conservative Solutions, the super PAC that supports Rubio, announced on Saturday night that it is embarking on a multi-state fundraising effort, starting with Nevada on Tuesday, to help elevate Rubio's standing to frontrunner.

Rubio is aware of his role as the new establishment counter force to Trump.

"We have to nominate someone that will bring us together as a party, that will grow it, that can take our message to new people and more importantly that can win, someone that's going to win in November," Rubio said Sunday morning on ABC's The Week. "I give our party the chance to nominate someone as conservative as anyone in this race."

Trump is by no means guaranteed to win the Republican nomination just by virtue of his triumph in South Carolina. It's important to keep in mind that the early primary states have all awarded their delegates proportionally, which means that Trump is not scooping up any majorities. He might have won a third of the votes in the states that have voted so far, but that also means 70 percent of the Republican electorate is voting against him. It's easier to come in first when the rest of the electorate is divided among half a dozen other candidates.

The big winner-take-all states don't have their primaries until March 15. After that, we'll find out whether the A.T. era will continue through November.

Follow Olivia Becker on Twitter: @obecker928