I actually don't think polls are overestimating Trump by much, more that they're underestimating Haley. And I think it really comes down to undecided voters. Trump is a known quantity for pretty much everyone in America. So anyone who isn't sure if they're going to vote for him isn't unaware of his issues, but probably has some doubts about him. So my theory is that undecided voters skew, if not anti-Trump, at least Trump-skeptical and are disproportionately choosing Haley. You can see an inkling of that in the preliminary exit poll data: In Virginia, for example, voters that decided their vote choice earlier than this year went overwhelmingly for Trump (78 to 21 percent), but voters that made their decision later chose Haley (54 to 42 percent).

—Mary Radcliffe, 538

Polling nowadays is incredibly hard. Seeing response rates of under 2 percent is all too common. So even very slight differences in how fired up people are to take polls can translate into meaningful differences between polls and results. Primary polling is especially hard because you can't use partisan identification to benchmark how reasonable the sample looks. That all said, in New Hampshire and in South Carolina, I wonder if Haley may have benefited from the lack of a competitive Democratic primary, and the fact that some who might have otherwise voted in a Democratic primary were able to vote for Haley.

—Dan Hopkins, 538 contributor

What's everyone's favorite theory about why polls have seemed to consistently overestimate Trump support? (I know this was discussed some on the podcast.)

—Julia Azari, 538 contributor

Tonight I'll also be watching my home state of Arkansas, where polls just closed. There hasn't been recent polling on the GOP presidential primary there, but Trump remains popular in the conservative state, which he won 62 percent of the state in the 2020 general election. His former press secretary is the governor, Gov. Sarah Huckabee Sanders, and she endorsed him in the fall.

There's not much suspense downballot either. Rep. Steve Womack, who represents the northwest corner of the state—home to the University of Arkansas, Walmart, and other big businesses and booming towns—is fending off an unlikely challenger from his right and is the only Republican incumbent to face a challenger. That challenger, State Sen. Clint Penzo is against vaccines, the war in Ukraine, government spending and has criticized Womack's votes during the House speaker fight last fall. But Womack has represented the district for 13 years and all the advantages of incumbency.

On the Democratic side, all four candidates for the House are running uncontested.

Perhaps of a bit more interest — earlier, I wrote about the state Supreme Court races and how the outcomes there could result in a game of musical chairs leading the very conservative Sanders to make one or two appointments to the court.

—Monica Potts, 538

Yesterday, the Supreme Court rejected the legal arguments claiming that Trump could be disqualified from running for president in 2024 because of his connection to the Jan. 6 insurrection at the U.S. Capitol. Section 3 of the 14th Amendment states that anyone who held a public or constitutional office and has engaged in insurrection is ineligible to hold office in the future, unless Congress passes a law stating otherwise. Section 5 says that Congress can also pass laws to enforce any of the provisions in the amendment. Lawsuits in several states came forward to disqualify Trump on these grounds.

But until recently, very few people had given much thought to this part of the 14th amendment since the years immediately following the Civil War. Legal scholars brought up a couple of ambiguities — did it apply to the presidency, since a number of offices are named, but not the president? Do we have an agreed upon definition of what counts as participating in an insurrection and whether Trump did that in 2021? (Spoiler alert: No.)

The Supreme Court ruled unanimously that the state of Colorado could not disqualify Trump, though there were disagreements about how far to take that ruling. A majority held that Congress would need to pass a law in order to enforce Section 3. Though the unanimity of the ruling papered over some of the partisan politics, the timing was impossible to separate from political considerations, since it came just in time for today’s big round of contests.

—Julia Azari, 538 contributor