FiveThirtyEight has been tracking endorsements throughout the Democratic primary. There have been more than 150 of these so far, out of the fairly broad universe of potential endorsers that we’re monitoring. But most endorsements don’t make national news.

Tuesday night was an exception — probably the first time all cycle that an endorsement has led the news cycle. Just as the fourth debate was concluding, reports surfaced that at least two of the four members of the “The Squad,” a group of first-term congresswomen who are outspokenly on the left of their party and often critique their party’s leadership, would be endorsing Bernie Sanders. Specifically, Rep. Ilhan Omar of Minnesota has already officially announced her endorsement of Sanders, and Rep. Alexandia Ocasio-Cortez of New York will reportedly endorse Sanders at a rally in Queens this weekend. (Contrary to earlier reports, Rep. Rashida Tlaib of Michigan has not yet officially endorsed Sanders. A fourth member of “The Squad,” Rep. Ayanna Pressley of Massachusetts, has no imminent plans to endorse Sanders or anyone else.)

I have quite a few thoughts about this, which partly go to how I think Sanders’s campaign, and Elizabeth Warren’s, are going overall. If you want a takeaway headline, though, it’s basically that this is the kind of thing I’d want to see more of from Sanders. In other words, it’s good news for him, but it will be better news for him to the extent it presages a more coalition-oriented approach to running a campaign, which includes building alliances with diverse groups of voters and winning endorsements in an effort to expand his coalition. If, on the other hand, it signals a desire by Sanders to provoke an establishment vs. anti-establishment confrontation with Warren, I’m not sure that’s as helpful to him. OK, here we go: Nine quick-ish thoughts about the AOC and Omar endorsements of Sanders:

1. There’s reason to think endorsements matter. Historically, endorsements have been a good predictor of presidential primary outcomes, often rivaling early polls for how well they anticipate how the vote will eventually turn out. The theory behind the importance of endorsements, as perhaps best articulated in the book “The Party Decides”, has come under attack in recent years, mostly because Donald Trump’s nomination in 2016 despite a lack of support from Republican endorsers was a poor data point for the theory (to put it kindly). In addition, some Democrats who received a number of endorsements earlier this year, such as Amy Klobuchar and Cory Booker, have not yet gained much traction in the polls. Nonetheless, the theory has a fairly good long-term track record. Incidentally, the theory is not necessarily that the endorsements directly influence voters — for instance, that a voter says to herself “Senator Such-and-Such is endorsing Governor So-and-So; guess I’m going to vote for So-and-So!”. (Although, an endorser with as high a profile as Ocasio-Cortez could be an exception.) Rather, it’s that endorsements are a proxy for support from “party elites,” and that party elites’ preferences tend to be a leading indicator of voter preferences.

2. But endorsements matter more when they cross ideological lines — and these ones were more predictable for Sanders. Imagine that, rather than AOC and Omar, West Virginia Sen. Joe Manchin had endorsed Sanders on Tuesday night. That would have been quite surprising, given that Manchin is fairly conservative while Sanders calls himself a democratic socialist. It would have sent a signal, however, that Sanders’s populism could resonate beyond his left-leaning base. Ocasio-Cortez and Omar, by contrast, are more in line with Sanders’s current base, being both quite left-of-center and quick to rebuke the Democratic Party establishment. Those sorts of endorsements matter less, according to “The Party Decides.”

3. The timing was smart for Sanders, and will help to fend off the media narrative that his chances are fading. This is a very pundit-y type of observation, so I’ll be brief. But dropping these endorsements after a fairly strong debate for Sanders — and after concerns about the long-term viability of his campaign following his heart attack — strikes me as smart. It could contribute toward a “Bernie comeback!” narrative, especially if Sanders gets a boost in post-debate polls.

4. This is going to intensify intra-left fighting. Want a fairly safe prediction? The primary is going to get nastier. In my read of the various Warren vs. Sanders spats, they’re less about who is further to the left per se and more about how to achieve change, with Warren wanting to work within the Democratic Party and Sanders wanting to upend the Democratic Party and “the system” overall. (To bring about a “political revolution,” as Sanders might say.) One reason I’ve been skeptical about Sanders’s chances of winning the Democratic nomination is that while seeking to upend the system is perfectly valid as a theory of change, it’s a fairly hard way to win a party primary when the party sets the rules, those rules are designed to achieve consensus rather than to reward factional candidates, and voting is restricted in many states to party members. In any event, because Ocasio-Cortez and Omar have a somewhat anti-establishment message — although less so than Sanders himself does — their endorsements are likely to send additional tremors down emerging Sanders-Warren fault lines.

5. “The Squad” is a potential general election liability. A July poll by YouGov found all four members of “The Squad” with negative net favorability ratings among adults nationwide: -17 percentage points for Omar, -16 for Tlaib, -14 for Ocasio-Cortez and -11 for Pressley, although they remain relatively unknown to many voters. (I’d love to cite a wider sample of polls, but I can’t find many others that asked about Omar, Tlaib or Pressley. A number of earlier polls on Ocasio-Cortez found her with negative ratings, however.) They are reasonably popular among Democrats, of course, and Sanders’s objective for now is to win the nomination, not the general election. His campaign has sometimes tried to emphasize his “electability”, however, and these endorsements won’t necessarily be helpful in that respect.

“The Squad” isn’t popular with swing voters Democrats Independents Republicans Overall Representative Fav. Unfav. Fav. Unfav. Fav. Unfav. Fav. Unfav. Ocasio-Cortez 48 11 17 46 5 69 23 37 Omar 41 11 14 44 5 65 19 36 Tlaib 38 11 13 43 5 62 18 34 Pressley 35 9 13 32 3 55 17 28 Source: CBS News/YouGov Poll, July 17-19, 2019

6. Warren has some tough decisions about whether to lean to the left or the center. One tempting strategy for Warren might be to essentially concede that Sanders is further to the left than she is. Step back and let swing voters associate Ocasio-Cortez and Omar with Sanders, not her, for instance. That doesn’t necessarily mean giving up on voters who identify themselves as left-wing. But it would mean not trying to outdo Sanders by moving further to his left. And it might mean subtlety trying to convey the idea that she’s actually the compromise choice between Sanders on her left, and Joe Biden on her right.

This could be risky, for various reasons. Warren’s current coalition relies a lot on support from the left; 50 percent of “very liberal” voters in the most recent Quinnipiac poll say they prefer Warren, as compared to just 11 percent for Sanders. Meanwhile, trying to strike a middle ground has been difficult for candidates such as Kamala Harris. On the other hand, voters (backed up by a lot of political science research) tend to perceive more moderate candidates as being more “electable,” and electability perceptions have been a problem for Warren. Furthermore, she may eventually need to add support from voters who currently support Biden, and Biden has more support than Sanders, so she could have more to gain than to lose by moving very subtly toward the center.

7. Warren’s lack of endorsements deserves scrutiny. Regardless of her strategy, Warren has received conspicuously few endorsements. She’s currently fourth in FiveThirtyEight’s endorsement tracker, behind Biden, Harris and Cory Booker, and has received only four endorsements from members of Congress outside her home state. She also hasn’t received many endorsements in early states such as Iowa and New Hampshire. Maybe she doesn’t care about endorsements much — but if you believe in “The Party Decides” theory of the race, this is a reasonably big problem for Warren. At the very least, it might mean that party elites are leaving their powder dry and could be open to a candidate who makes a late surge, such as Booker, Pete Buttigieg or Amy Klobuchar.

8. Both Sanders and Warren need to expand their appeal to non-white voters, and this is a step in the right direction for Sanders. Ocasio-Cortez is Hispanic (Puerto Rican) and Omar is black (Somali-American). Warren has some nonwhite endorsers herself, such as Raul Grijalva, who is Hispanic, and Deb Haaland, who is Native American. But it’s a pretty white group, as are Warren’s voters. According to YouGov polling for The Economist, Warren has the support of 31 percent of white Democrats, as compared to 15 percent of blacks, 17 percent of Hispanics and 21 percent of voters of “other” nonwhite races.

As for Sanders, his supporters are more diverse than Warren’s in one sense, in that his numbers are fairly even across different racial groups: He has the support of 14 percent of whites, 11 percent of blacks, 19 percent of Hisapnics, and 17 percent of “other” voters, per YouGov. On the other hand, he isn’t actually doing better than Warren with nonwhite voters — she actually has slightly more nonwhite support than he does, according to YouGov (except among Hispanics). Rather, it’s that she’s doing really well with white voters, while his numbers are flagging. In some ways, Warren is starting to replicate the 2016 version of the Sanders coalition, when Sanders won the support of 47 percent of white voters, 26 percent of blacks, and 36 percent of Hispanics, according to the CCES.

To put it another way, Sanders’s support is diverse, but not especially deep, while Warren’s is deep, but not especially diverse. Both of them could stand to gain ground among black, Hispanic and other nonwhite voters, and winning the support of endorsers like Omar and Ocasio-Cortez is good news for Sanders in that regard.

9. Overall, these endorsements could be consistent with a coalition-building approach, which would be a good plan for Sanders. Speaking of expanding one’s coalition: So far, Sanders has not done all that much to expand beyond his current base of support, as I mentioned before. His numbers have been steady in the polls for months, but “steady” isn’t that helpful when you’re polling at only 15 percent — you’ll need more than that to win primaries and caucuses. He’s winning very few voters who didn’t vote for him in 2016, while having lost about two-thirds of the ones who did choose him in 2016 to Warren and other candidates. His team may have miscalculated, thinking that the Sanders base might have been, say, 20 to 25 percent of the electorate rather than 15 percent. It also may have underestimated both Biden and Warren.

But if the critique is that Sanders’s base isn’t broad enough on its own, getting endorsements from the likes of AOC and Omar is at least nodding in the right direction. Sure, it might have been better if they were “against type” endorsers (see point No. 2). But almost any type of endorsement is consistent with a coalition-building strategy, something Sanders has sometimes eschewed in the past even though it’s usually the easiest way to win a party nomination. If Sanders’s campaign uses these endorsements to build momentum toward that strategy — what I sometimes think of as a “kindler, gentler” version of Sanders who is trying to make a broad range of Democratic voters feel at home in his coalition — they could be a turning point in his campaign. If instead they’re a precursor to more left-on-left infighting, probably less so.