Donald Trump has won the Virginia Republican primary. He's won a state Marco Rubio hoped to win in the closing hours of voting, and where the Republican electorate has historically been wealthier and better-educated than elsewhere in the South.

In polls taken in the two weeks before the election, he was leading by double digits. But Virginia took far longer to call than other states voting Tuesday due to a strong performance by Rubio.

Virginia awards its 49 Republican delegates proportionally. The votes are still being counted, but if Rubio finishes with a healthy share of the vote — and he is likely to— he could pick up a number of delegates as well. Even candidates who didn't perform as well could end up slightly bolstering their delegate count.

Virginia could have been Rubio-friendly

Compared with the other states that voted Tuesday, Virginia could have been hostile territory for Trump. Its voters in the past two primaries were more likely to be college-educated, suburban, and high-income — demographics that have been more likely to support Rubio in past contests.

And Rubio picked up endorsements in the state from two members of Congress, Reps. Scott Rigell and Barbara Comstock.

But two factors could help explain Trump's success. First, the electorate itself might be different: Republican turnout has been up nationwide, and first-time voters have voted heavily for Trump. This is also the first time Virginia has voted on Super Tuesday. Past contests were less competitive because candidates had already dropped out.

Second, even though Rubio generally performs better in the suburbs than overall, it's not as if he's been trouncing Trump with those voters. One of the striking features of Trump's campaign has been how it crosses divides within the Republican Party. Although college-educated voters are friendlier to Rubio, as are those from high-income families, many of those voters are still choosing Trump.

Trump is looking unstoppable

Despite Rubio's likely success at picking up some delegates, the story of the night is the unstoppable juggernaut that Trump has apparently become. Ahead of Super Tuesday, he was polling strongly in seven of the 11 states where Republicans voted. Three of the remaining four states simply hadn't polled enough to tell. And Trump appears to be on track to win at least most, if not all, of them.

Virginia's rules for awarding delegates mean that other candidates, particularly Rubio, could come out with delegates as well. Rubio might even try to declare victory, as he has in other states where he finished second.

But the more states that Trump wins outright, the harder it is for Rubio to argue that his losses are actually victories.