Let's not sugar-coat this: If the polls are right, Haley will lose badly to Trump in South Carolina, her home state, tonight. According to 538's average of polls, Trump commands the support of 62 percent of likely primary voters compared with Haley's 34 percent. Haley has gained ground in recent weeks, likely a result of voter consolidation as the rest of the candidates dropped out after voting in Iowa and New Hampshire, but so has Trump.

Moreover, according to a poll released this week by Suffolk University/USA Today (which had a very similar breakdown to our average), Trump is leading Haley with most major demographics in the state. The former president leads among Republicans and conservatives, groups that make up 76 and 81 percent of Republican primary voters in the state, respectively. Haley, meanwhile, holds an almost 20-point lead among respondents who described themselves as moderate or liberal and a 26-point lead among those who say the most important issue is the future of democracy.

According to my colleague Geoffrey Skelley, if Trump wins by as much as the polls imply, it would be the best-ever performance for a non-incumbent presidential candidate in South Carolina primary history. (The current record is George H.W. Bush's 28-point win over Bob Dole in 1988.) Surely the Haley campaign will try to spin a victory out of defeat — Trump is no easy opponent, to be fair — but with these numbers there's simply no denying Trump's strength.

—G. Elliott Morris, 538

Polls are open in the Palmetto State, the latest battleground in the GOP presidential primary race. You'd be justified in asking if this will also be the contest's last battleground, as Trump's commanding lead in the polls suggests he'll almost certainly walk away with all the delegates tonight and continue his march to the nomination. We'll certainly be looking out for Haley to signal what she'll do next: She's insisted that she plans to stay in the race, but a big home-state loss could throw cold water on an already-struggling campaign.

As for the timing of it all, polls will close at 7 p.m. Eastern, and we wouldn't be surprised if a winner is projected not long after. As usual, though, we plan to stick around to analyze results and candidate speeches throughout the evening. We'll also discuss how Trump got to be the overwhelming favorite on Haley's home turf, whether there are any upsides for Haley as the last challenger standing and (gulp) what it all means as we turn toward November's general election.

—Tia Yang, 538