The first national poll following the Nevada caucuses, from CBS News/YouGov, suggests that Sen. Bernie Sanders remains the national frontrunner. Everyone else is in a scramble.

The online poll of 6,498 Democrats and independents planning to participate in Democratic primaries and caucuses was conducted from February 20 to 23, and found that Nevada — and the debate before it — has changed the outlook for a number of campaigns yet again.

Bernie is solidifying his frontrunner status, a position he seized ahead of the New Hampshire primary, and has solidified with his win in Nevada with 28 percent support. But while most recent national polling has found former Vice President Joe Biden or former New York City Mayor Mike Bloomberg in second place, YouGov’s work found Sen. Elizabeth Warren to be second, with 19 percent support, likely due to her strong debate performance ahead of the Nevada caucuses. Biden was third, with 17 percent support; Bloomberg fourth at 13 percent; former South Bend, Indiana, Mayor Pete Buttigieg was fifth, with 10 percent; and Sen. Amy Klobuchar sixth, with 5 percent support.

The poll’s margin of error is 1.7 percent, making Sanders’s lead secure. Warren’s lead on Biden, however, is in that margin of error, meaning the former vice president could actually be in second place, as he has been in other surveys. Nevertheless, the poll is Warren’s strongest in months.

The first post-Nevada caucuses poll was full of good news for Warren and Sanders

The effect of that debate was apparent Saturday — Nevada entrance polls found that caucus-goers who made up their minds at the last minute favored Warren by 7 percentage points compared to those who voted early (the debate was held three days ahead of in-person caucusing but after the conclusion of early caucusing). And 50 percent of likely Democratic primary voters told YouGov that Warren was the last debate’s most impressive candidate.

Whether Warren can maintain, or even build on, this apparent post-debate bump remains to be seen. Former candidates, such as Sen. Kamala Harris, also saw marked increases in support following strong showings in debates but were unable to hold on to those gains. And with the South Carolina primary and Super Tuesday just around the corner, whether the Massachusetts senator can avoid this fate will be key.

As Vox’s Li Zhou has explained, the Warren campaign has invested heavily in a strong showing on Super Tuesday, and YouGov’s results suggest that investment may be paying dividends — not just because the poll puts the senator in second place, but because it also found her to be directly behind Sanders when likely primary voters were asked whom they were considering: 48 percent said they were considering Sanders, and 44 percent said they were thinking about voting for Warren.

Pollsters also found likely voters thought Sanders and Warren would best represent them: When asked which candidate “will fight for people like you,” 57 percent said Sanders would do so “a great deal,” and 53 percent said the same of Warren; their closest competition on this metric was Biden, who 34 percent said would fight for them a great deal.

Being under consideration is important because — as was the case in many of the states that have caucused and voted so far — voters nationally have not yet settled on a candidate: 42 percent said they know for sure whom they’ll vote for, but 58 percent were not sure.

Picking up the support of these uncertain likely voters would be key for any candidate — that’s the majority of the likely electorate — but is of particular import to Sanders, who needs to win the next few contests by large margins in order to win enough delegates to eke out a commanding lead over the field. And other candidates, from Warren to Biden to Buttigieg, will likely see those voters who aren’t yet set in stone as valuable opportunities to make up for disappointing delegate hauls in the first few contests.

One unknown in all of this is how Bloomberg’s ad strategy will affect these results — so far, he has spent more than $400 million of his own money running multi-platform ads across the country, and has begun to signal a willingness to run attack ads, particularly ones targeted at Sanders.

We now know how he performs in debates but have not yet seen how he actually performs in a primary. The YouGov poll does suggest, however that likely primary voters don’t hold an overly charitable view of the former mayor’s campaign spending: 18 percent said his strategy of ignoring the first four Democratic contests and pouring his money and attention into Super Tuesday shows he is “trying to take a shortcut instead of campaigning,” and 43 percent said his campaign shows “that rich people can have too much influence in politics.”

The YouGov poll is only one look into what’s been a dynamic race, and its findings could change considerably following the South Carolina primary. But it is a good reminder that while Sanders’s rise is real, his lead is not overwhelming, giving the ever-changing collection of rivals immediately in his wake a chance of picking up enough delegates on Super Tuesday to threaten his chances of becoming the presumptive nominee.