We started getting some clarity in the Republican and Democratic races Saturday night. Hillary Clinton squeaked out a win in Nevada — but did so in a way that suggests she has, despite Bernie Sanders's strength, maintained her national advantage.
Marco Rubio's strong showing in South Carolina helped push Jeb Bush out of the race, giving Mr. Rubio a chance to unify the mainstream of the Republican Party and bring about a true three-way race.
When Donald Trump won New Hampshire, he won it in two ways: He won the most votes, while the establishment was divided by a split result among its ranks.
Tonight, Mr. Trump won with nearly the same share of the vote. But he might lose once and for all what has been his biggest advantage: the divided Republican field.
With 99 percent of the vote reporting, Mr. Rubio holds 22.5 percent of the vote. It might not seem an impressive figure, but it meant he finished well ahead of Mr. Bush, who holds just 7.8 percent of the vote. It was enough to force Mr. Bush out of the race.
It is hard to overstate how important Mr. Bush's departure is to Mr. Rubio. No, Mr. Bush did not hold a large number of votes (though I would note that the sum of Mr. Rubio and Mr. Bush's support would have been very close to Mr. Trump's total, and well ahead of Mr. Cruz's).
But he held a large number of donors and officials in his camp, and he kept as many or more on the sidelines. His presence prevented any other Republican from consolidating the power of the mainstream wing of the party. The fighting among the mainstream Republicans hindered them from focusing an attack on Mr. Trump.
The combination of Mr. Rubio's strong showing and Mr. Bush's exit could bring about a "party decides" moment — the rapid consolidation of the mainstream of the Republican Party. It could mean a flood of endorsements and donations to Mr. Rubio ahead of Super Tuesday on March 1.
The benefits to Mr. Rubio could be huge. He will have more endorsements, more money, and he will now be free of the attacks from the Jeb Bush super PAC Right to Rise and his other mainstream rivals. He will have more votes available as well.
Mr. Bush's exit would be enough to make tonight a win for Mr. Rubio, but Mr. Rubio's share of the vote is impressive as well. Most important, he cleared 20 percent of the vote — a crucial delegate threshold for many Southern states on Super Tuesday (although not South Carolina tonight). If he can't exceed that number in states like Alabama, Texas, Georgia and Tennessee, he will receive no delegates in those states. It's a good sign that he's near or above this number even after the disadvantage of a divided field and after a weak showing in New Hampshire.
The number of votes at stake is potentially considerable: Mr. Bush and Mr. Kasich currently combine for 15.4 percent of the vote, and that support would seem likely to break toward Mr. Rubio.
As for Mr. Trump, there's no question that his showing was strong. No matter how you cut it, around 33 percent of the vote is a big number in a divided field. He outperformed the final polls, which showed him slipping toward or under 30 percent. He may win all of the state's 50 delegates, since the state awards its delegates on a winner-take-all basis by congressional district and statewide. His tally is very near the number he would need to prevail in a three-way race.
The question is whether he'll be able to maintain his position as the field narrows, and whether the field will narrow fast enough. That's his real test, and he hasn't faced it yet. He will now.
If Mr. Rubio and Mr. Trump have a real case for a victory, Mr. Cruz does not.
Mr. Cruz's campaign has always argued that his path to victory hinged on uniting "very conservative" voters and the religious right. South Carolina was the opportunity to do it: Evangelicals represented more than two-thirds of the electorate.
Mr. Cruz, in fact, is not even doing better than past evangelical favorites like Mike Huckabee or Newt Gingrich. He currently trails Mr. Rubio, who has the burden of a divided field.
Mr. Cruz is poised to struggle outside the South. His 12 percent share of the vote in New Hampshire was telling in that regard, and so was his weak showing in South Carolina's moderate coastal enclaves (he's currently trailing John Kasich in Hilton Head, for example).
If Mr. Cruz can't win the South by a big margin, he's not going to win the nomination. At the moment, he's not winning at all.
Hillary Clinton's victory in the Nevada caucus on Saturday suggests that her national advantage, although diminished, has survived a big loss in New Hampshire and a tight race in Iowa.
Nevada is fairly representative of the national electorate, and it's a state where Bernie Sanders would be expected to fare slightly better than he would elsewhere. (The Nevada Democratic electorate is about as white as the national average, with a slightly smaller share of the black vote than the national average.)
Mr. Sanders's supporters will undoubtedly protest this framing. Their candidate exceeded the expectations of a month ago, and he fared better among Hispanic voters than many would have guessed. Mrs. Clinton's lead is only five percentage points with 88 percent of precincts reporting.
But judging Mr. Sanders merely by whether he makes life tough for Mrs. Clinton diminishes his candidacy. It assumes that he's just a protest candidate who should be judged by a lower standard. If he is taken seriously, and judged by whether he's on a path to the nomination, then his performance today fell short.
Mrs. Clinton won by carrying Las Vegas's Clark County — the most diverse in the state — by a 10-point margin. She won the majority Hispanic precincts in East Las Vegas, calling into question the entrance-exit poll finding that Mr. Sanders won the Hispanic vote.
The entrance-exit poll showed Mr. Sanders leading by eight points among Hispanic voters. The poll was small, with just 1,024 voters, and that makes it hard to measure a small subgroup. Hispanic voters are heavily concentrated in small areas, and these polls are conducted at individual precincts. If the precincts, simply by chance, are off, then the results for a small subgroup can also be off.
This is how the exit polls showed George W. Bush winning 44 percent of the Hispanic vote in 2004. Merely by chance, 3 of the 11 predominately Hispanic precincts were in heavily Republican Miami-Dade County. (The best estimate is that Mr. Bush actually won 40 percent of the vote, based on a compilation of the 50 state exit polls.) The danger is even greater with a poll of the size today.
More generally, the entrance-exit poll showed Mrs. Clinton and Mr. Sanders in a virtually tied race, so we know that the poll understated Mrs. Clinton's support somewhere.
The results by precinct also indicate that Mrs. Clinton fared extremely well among black voters. In six precincts identified as majority black by The Upshot, Mrs. Clinton won the delegate count by a staggering 96-7. The entrance-exit poll showed her with a 76-22 percentage advantage among African-Americans.
It bodes well for Mrs. Clinton in the South, starting with South Carolina next weekend.
Nevada was the third-straight state where, because of demographics, one would have expected Mr. Sanders to fare better than the national average. In terms of the Democratic primary electorate, the black voter share in the state is below the national average. If African-Americans are the principal source of Mrs. Clinton's national advantage, as her strength with them today and her modest showing among Hispanic voters suggest, then she should be expected to fare better elsewhere.