(Matt McClain/ The Washington Post)
Opinion writer

THE MORNING PLUM:

The California Democratic primary is tightening, and a Bernie Sanders victory on June 7th — while not altering the final outcome — would no doubt persuade him and his supporters to push for maximum concessions, perhaps all the way to the floor of the Democratic convention in Philadelphia.

But no matter how contentious things end up getting, Democrats are very likely to unify in the end. A new analysis by political scientist Alan Abramowitz explains why: Democratic voters really like Barack Obama, and they really hate Donald Trump.

Abramowitz, a professor at Emory University, looked at the 2008 Democratic primary outcome and compared it to what is coming. Relying on American National Election Study data, Abramowitz showed that Democrats and Dem-leaning independents supporting 2008 primary loser Hillary Clinton ended up voting overwhelmingly for Barack Obama in the general election — even though a sizable percentage of Clinton supporters regarded his GOP opponent John McCain favorably. Crucially, this is because many of the independents who had supported Clinton against Obama were Democratic leaning ones, and ended up favoring Obama as the general election progressed. (Right now, many of the independents backing Sanders are also Democratic leaners.)

If anything, Abramowitz concludes, party unity could be easier this time, because Trump is vastly more disliked by Democratic voters than McCain was in 2008:

Trump has far less appeal to Democratic voters in 2016 than McCain had in 2008. According to the 2008 ANES data, McCain was viewed favorably by 23% of all Democratic identifiers and leaners and unfavorably by 58%. In contrast, according to four recent national polls — CNN, Fox News, CBS News/New York Times, and Public Policy Polling — Donald Trump is viewed favorably by only 5% to 12% of Democratic voters and unfavorably by 82% to 89%. And while these polls did not provide data on Trump favorability among Clinton and Sanders supporters, it seems unlikely that he is viewed more favorably by Sanders voters, who tend to be, if anything, further to the left and more suspicious of billionaires than Clinton supporters.

Of course, there are meaningful differences between 2016 and 2008. Sanders and Clinton legitimately have bigger ideological differences than Clinton and Obama did. Young voters make up a big chunk of Sanders supporters, and they could potentially prove tougher to win over or harder to turn out. But that’s where Obama comes in:

A somewhat greater concern for Democrats in 2016 may be ensuring that Sanders’ youthful supporters actually make it to the polls. A much larger share of Sanders backers than 2008 Clinton backers are under the age of 30, which means they are probably less reliable general election voters. The Clinton campaign clearly will need a strong get-out-the-vote effort and all the help they can get from Sanders in motivating his young supporters to turn out in November. But someone else should also be able to help a great deal with the task of unifying Democrats and increasing turnout among Sanders supporters: President Obama. Fortunately for Clinton, Obama is extremely popular with Democratic voters, including Sanders supporters. In the latest NBC News/Wall Street Journal national poll, Obama’s approval rating among Democrats was 88% and his approval rating among Sanders primary voters was 82%.

And so, Obama’s rising approval ratings could help Clinton twice — not just in the general election against Trump, but also with regard to unifying the party behind her after the primaries.

How Clinton and Sanders manage these unifying efforts will of course matter. But all indications are that Clinton knows it’s in her interests to make concessions that encourage a smoother resolution. Meanwhile, the incentives may end up pointing towards Sanders helping to unify the party: He is poised to maximize his influence after the election, and doing all he can to keep his supporters engaged in the battle against Trump could actually help in that regard. Beyond all this, Elizabeth Warren’s big speech this week attacking Trump as a cruel, selfish capitalist cutthroat and con artist, and framing the election as a stark choice between Trump’s fraudulent pro-rich economic agenda and concrete Democratic policies designed to improve people’s economic prospects, hints at a powerful unifying populist argument against Trump that Sanders (despite his hopes for more transformative change than Clinton will push for) would be well suited to make.

In this context, note that there’s a lot of chatter today about the possibility of a Trump-versus-Sanders debate. Trump joked about it on late night TV yesterday, and Sanders promptly accepted the challenge, tweeting: “game on.” It’s a great idea. It would feature Sanders making a case against Trump that his supporters would thrill to, getting them focused on the reality of the threat of a Trump presidency — that is, if it actually happened. Trump, of course, is unlikely to go through with it, since he’s actually a relatively weak debate performer, and Sanders would probably unmask his buffoonery pretty effectively. But if the idea gains real currency, it could end up unleashing a round of stories about how Trump won’t even go head to head with the guy he likes to dismiss as “crazy Bernie.”

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* TIGHT RACE IN CALIFORNIA: A new Public Policy Institute of California poll finds that Hillary Clinton leads Bernie Sanders by only two points among likely Democratic primary voters in delegate rich California, 46-44. The polling averages have a much larger spread, with Clinton leading by 56-39. But the Clinton campaign (along with the Sanders campaign) is advertising in California, which suggests the Clinton team thinks it could get very close.

A Sanders win would unleash a roar of punditry about her “weakness.” But the fact is that if it’s close, Sanders has no chance of closing the gap in pledged delegates, particularly since he’s very likely to lose New Jersey, the only other state with a large delegate haul.

 * TRUMP MAY BE UNDER-PERFORMING IN RUST BELT: A new Bloomberg poll finds that Donald Trump is trailing Hillary Clinton by seven points among middle income Rust Belt voters, and may even be under-performing among Rust Belt whites:

Likely voters with annual family incomes of $30,000 to $75,000 in Michigan, Ohio, Pennsylvania, and Wisconsin back Clinton over Trump, 46 percent to 39 percent…The findings should sound an alarm for Trump because they show he’s failing — at least so far — to dominate among the sort of voters thought to be more sympathetic to him….When only the white middle-income participants are considered, the billionaire beats Clinton 44 percent to 40 percent.  That’s behind where Republican Mitt Romney finished.

It’s still early and this is only one poll, so don’t place too much stock in it, but maybe it’s time for folks to bring some skepticism to bear on claims that Trump can ride a wave of Rust Belt white anger into the White House?

 * TRUMP IS DEMOLISHING GOP’S MODERNIZATION EFFORTS: Joshua Green has a great piece of reporting on how Trump’s candidacy is wrecking RNC chairman Reince Priebus’ hopes of modernizing the GOP and broadening its demographic appeal. Fun nugget:

[Trump’s] vision of the GOP’s future is in many ways the diametrical opposite of what Priebus and the party establishment had imagined….”I think he’s gonna win,” [Priebus] kept saying. But he was getting angry. When I suggested Trump’s hostile takeover was ruining his push to modernize the party, Priebus snapped that I didn’t know what I was talking about. A moment later, he apologized: “I hardly ever get testy.”

Something tells us that ol’ Reince will be getting a whole lot testier than this before long.

* BERNIE BUILDS POWER IN THE SENATE: Politico looks at how Bernie Sanders’s presidential run is translating into increased power and visibility in the Senate:

The Vermont senator…is throwing his weight against some of the most significant bipartisan deals pending in Congress this year. He’s actively urging Senate Democrats to reject a deal reached by House Republicans and the Obama administration to ease Puerto Rico’s debt crisis and has emerged as one of the few opponents of a landmark overhaul of chemical safety laws — the first major environmental legislation in a generation. Sanders is poised to be more powerful than ever, backed by more than 2 million Twitter followers and millions more admirers nationwide who’ll be looking to him to help set the progressive agenda.

This is another reason why it may be in Sanders’s interests to help unify the party against Trump — he can look forward to exerting more influence over the party’s governing agenda later.

* REPUBLICAN PARTY CONTINUES ENABLING TRUMP: E.J. Dionne has a nice column explaining how much Trumpism has in common with European nationalist parties, and pinning the blame for his rise and continued strength on the GOP:

Moderate conservative parties have seen some of their own natural constituents drawn away by rising anti-immigrant feeling….Here again, the Trump analogy holds: Mainstream Republicans winked and nodded toward a hard line on immigration; Trump has embraced it whole with his calls for a border wall and a temporary ban on admitting Muslims to the country….Standing up against the new far right should be a shared task across the old political divides in all democracies. But Republican politicians are falling in line one by one behind Trump, choosing to ignore the threat he poses to political decency and his challenge to democratic values themselves.

It will be fascinating to see if Saint Paul Ryan becomes another enabler of this.

* STOP WORRYING SO MUCH ABOUT THE POLLS: The Upshot offers a very useful look at how predictive the national polls have been at this point in the last nine presiential elections. Conclusion:

At this point – 167 days before the election – a simple polling average has differed from the final result by about nine percentage points. We expect this average to become more meaningful by the week, until the national party conventions temporarily make it less so, as shown in the bump about 100 days before the election. The average difference begins to flatten about two months before the election….But this far out, a simple polling average is not particularly helpful at predicting the final result.

So don’t worry yet! There are more than five months to go. If you must obsess over the polls, stick to the averages, and the averages of state polls.

* AND WORLD LEADERS ARE ‘RATTLED’ BY TRUMP’S RISE: President Obama said this at a press conference in Japan this morning:

Obama…told reporters that “it’s fair to say” world leaders are “surprised” Trump is the presumptive Republican nominee. “They are not sure how seriously to take some of this pronouncements but they’re rattled by him — and for good reason, because a lot of the proposals that he’s made display either ignorance of world affairs or a cavalier attitude,” Obama added.

Yeah, and so what? Trump is gonna come in, bash their heads together, and put an end to their collective ripping off of America. Of course the weenies are rattled!