We have chronicled the storied and checkered campaign launch of Massachusetts Sen. Elizabeth Warren. From the dark days of her New Year’s Eve Instagram live stream of chugging a beer, to ongoing issues over her prior claims of being Native American, Warren has had some rough and cringeworthy patches.

However, her tenacity has been paying dividends in recent months as at least some voters have forgotten or forgiven her prior offenses, and her polling support continues to blossom.

The race has stagnated into a conventional polling form of Joe Biden in first-place, with Bernie Sanders in second-place in practically every poll. That was the norm, until this week, when Bernie began losing ground and Warren began picking up support, as Politico reports:

Warren has overtaken Sanders nationally, according to a new Economist/YouGov poll, which puts the Massachusetts senator ahead of her Vermont counterpart 16 percent to 12 percent. Former Vice President Joe Biden still leads all contenders with 26 percent support.

Warren also polls ahead of Sanders in Nevada, where Democrats will caucus next February after the Iowa caucuses and New Hampshire primary. Biden leads the first Monmouth poll of likely Democratic caucusgoers in Nevada with 36 percent support, followed by Warren at 19 percent and Sanders at 13 percent.

On average, of course, Bernie is well ahead, but he has lost some steam in recent weeks. If you study the trends, there is one notable point at which Bernie appears to have started losing some momentum in his quest to serve as the progressive alternative to voters who aren’t keen on Joe Biden.

Voting rights for terrorists?

Flashback to late April, when Bernie appeared on a CNN town hall and was asked about voting rights. His answer was absolute and to the point, that every citizen deserves the right to vote, even if they’re in prison for violent crimes, per CNN:

And, Sanders said, enfranchising people like Dzhokhar Tsarnaev — the US citizen who helped bomb the Boston Marathon in 2013, killing three and injuring hundreds of others — is a part of that.

“Yes, even for terrible people, because once you start chipping away and you say, ‘Well, that guy committed a terrible crime, not going to let him vote. Well, that person did that. Not going to let that person vote,’ you’re running down a slippery slope,” Sanders said when asked by a student if sex offenders, the Boston Marathon bomber, terrorists and murderers should have voting rights.

For some Democrats, even those who support a liberal overhaul of voting rights restoration, plainly stating that even murderers and terrorists in prison should still be allowed to vote was a step too far.

The CNN story goes on to note that Bernie took rebukes on this question from Mayor Pete Buttigieg and Sen. Cory Booker, while Sen. Kamala Harris was non-committal on the matter.

Days later, following Bernie’s CNN town hall on April 22, Joe Biden announced his candidacy and the field hasn’t been the same since. Sure, Bernie has kept up with second-place for the most part, but his broader support has been deteriorating.

Why is Warren benefitting?

The details can be found deeper in the polling data. There is a slice of voters who are progressive, but not quite as progressive as Bernie professes to be as a “democratic socialist.” His ideas are widely enjoyed, for the most part, but there is a fear among some Democrats that he’s simply unelectable at a national level, partly for statements such as the voting rights for felons comment, and partly because of his views which sit far to the left of where many moderates and independents are:

While Biden has dominated the centrist lane, Warren and Sanders have competed for the party’s left flank. In the Nevada poll, Biden leads the field with moderate and conservative Democrats (47 percent) and somewhat liberal voters (31 percent). Warren narrowly bests Sanders with very liberal voters, 27 percent to 26 percent, but she outperforms him threefold with somewhat liberal voters, 24 percent to 8 percent.

She also ranks at the top as voters’ second choice, though the margin between Warren, Sanders, Biden and California Sen. Kamala Harris is all within 2 percentage points.

In the Economist/YouGov survey, Warren’s net favorability is slighter higher than Sanders’, -6 percent to -7 percent, but Sanders is tied with New York Mayor Bill de Blasio for the candidate whom likely Democratic voters would be most disappointed to see win the nomination. [Emphasis added]

The last sentence, which I emphasized, is probably the part that will slowly eat into Bernie’s polling support over time, nudged by his statements from time to time which peel moderate Democrats off his bandwagon.

Let’s not pretend, however, that Bernie is down and out. His support stems from a strong core of voters who have stuck with him since 2016. He won’t drop much further before hitting a floor of support which will carry him deep into the primary season.

Warren also benefits, as noted above, from earning “second choice” support over Bernie. For voters who aren’t thrilled with Biden’s establishment pedigree, but unsure about Bernie’s ability to win nationally, Warren presents an option right now that cuts a little in between.

Unlike Beto O’Rourke, who keeps dropping further into polling oblivion, Elizabeth Warren has somehow managed to stand out among the crowded field and improve her position in these early months before the campaign really kicks into gear.

This battle between Bernie and Warren will be one to watch on the debate stage later this month.