In order to get to 1,237 delegates before the convention, Donald Trump needs to sweep both New York and California primaries. That may not be much of a problem in New York, as Trump dominates the field in the RCP average by 32 points, and gets the majority he needs for a winner-take-all haul of the statewide delegates in all four recent polls. With that kind of lead, it’s difficult to imagine Trump losing any of the delegates from Congressional districts in New York, so he should get all 95 delegates.

California, however, looks like a much different story. It has 172 delegates at stake, 159 in the CDs, and Trump needs most of these to get to the majority required to win on the first ballot. According to SurveyUSA, though, his lead in the Golden State isn’t anywhere near as dominating as on his home turf:

Extremely unscripted Donald Trump is viewed extremely unfavorably by half of California’s registered voters and by 15% of Republicans most likely to vote in the state’s 06/07/16 GOP Primary, according to research just completed by SurveyUSA for television stations KABC in Los Angeles, KPIX in San Francisco, KGTV in San Diego, and KFSN in Fresno. 71% of CA women and 75% of CA Latinos view Trump negatively today. But even with this anchor tied to his foot, Trump at this hour continues to lead Ted Cruz, though narrowly, among likely Republican primary voters.

Today, it’s Trump 40%, Cruz 32%, John Kasich 17%. Trump still leads among women, though his comments about women, and his staff’s treatment of women, were in the news during the field period for this survey. Among moderates, Kasich and Trump run effectively even in the GOP Primary, 35% for Trump to 34% for Kasich, with Cruz at 10%. Among those who say they are “somewhat conservative,” Cruz leads Trump 44% to 38%. But among those who are “very conservative,” Trump leads Cruz 45% to 38%. Among primary voters with an “extremely positive” view of Trump, Trump defeats Cruz 8:1. Among those who are “neutral” on Trump, Cruz leads Trump 4:3. And among those who have an “extremely negative” view of Trump, Cruz defeats Trump 10:1. The contest is fluid; much could change between now and 06/07/16. To win all 172 of California’s delegates to the Republican National Convention, Trump, Cruz, or Kasich would need to carry every one of CA’s 53 Congressional Districts.

The sample size for the GOP primary is on the thin side at 356. Oddly, this is mid-range for other California polling in the recent RCP list. The gap in the SUSA poll is about the same as in the RCP average, too, at eight points. although this is the only poll that puts Trump at 40%. The poll with the largest sample size was Smith Johnson Research’s survey from early March (454 likely voters), which only had Trump up by five.

Interestingly, Trump leads by 15 points in the greater Los Angeles area, putting him in position to carry a number of CDs and grab those delegates. But Cruz has a 13-point lead in the Inland Empire region, suggesting that he’ll win some of those districts and delegates too. For good measure, Kasich leads in the Bay area 43/36, the only region in which he’s competitive, and might come away with a few delegates as well.

How does that impact the trajectory of the race? It depends on the projection. The Frontloading HQ projection from mid-March had Trump on pace to win 1279 delegates — but that depended on a total sweep of Wisconsin and California. However, that projection only had Trump winning 63 delegates in New York, almost certainly an underestimate of his strength. Nate Silver’s roundup of analysts a week later gave Trump 71 NY delegates, but also 25 from Wisconsin and 93 from California. That puts Trump short of the nomination by a mere 29 delegates:

If Trump does, in fact, get 1,208 delegates, he still might win on a first ballot. He would need only a fraction of the delegates that are currently unbound (or will be unbound) to reach 1,237.

Who exactly are these unbound or uncommitted delegates? Some, like the six from the Virgin Islands, were elected by voters to be “uncommitted,” but they may commit to a candidate closer to the convention. Others, like the 54 Pennsylvania district delegates, are automatically unbound and have been elected as unbound for decades (see: when Gerald Ford beat Ronald Reagan in the 1976 primary). These delegates are free to choose whichever candidate they want on all ballots.⁴ In addition, some delegates from candidates who have withdrawn from the race may become available to Trump, depending on the state’s rules. Although it’s hard to know Trump’s exact chance of getting 29 delegates from this group, Trump probably would have a decent shot at reaching 1,237.

Last week, I posited that such a slim margin would likely convince enough unbound delegates to throw in with Trump, too. But that depends on Trump winning a lot of CDs in California, as well as getting big hauls in Indiana and tonight in Wisconsin, too. So far, polling in Wisconsin and California doesn’t necessarily demonstrate confidence in that outcome.

Of this, there is little doubt: the nomination will come down to the wire. And if recent California polling turns out to be accurate, we’re very likely to have the first multi-ballot convention in almost 70 years.