Fighting won't kill the Democrats. It will only make them stronger.
You can hear the cries of horror from within the Democratic Party about the upcoming release of Hillary Clinton's book about the 2016 campaign, What Happened. Why open these wounds over her primary campaign with Bernie Sanders? Can't we move on? Meanwhile, Bernie backers are out picking fights to the chagrin of party stalwarts.
But Democrats should relax. This kind of internal squabbling is completely normal. Not only won't it do them much harm, it will probably help them in the long run. And with three years before the next presidential election, this is the time to do it.
There's no way you can avoid a little recrimination after a presidential loss, particularly one as wrenching as 2016. And even if the party doesn't need some kind of major overhaul, it can always use a debate about what its priorities should be and how to present them to the voting public. Some of that's happening now — just look at how single-payer health care is rapidly becoming consensus within the Democratic Party. As that happens, Democrats are having a (hopefully) enlightening discussion about exactly what it would involve and what the tradeoffs are, both in terms of policy and politics, which will put them in a much better position to actually enact some form of universal coverage the next time they get the chance.
At the same time, some people are using it as a litmus test, saying they can't support a candidate who won't agree to their particular version of single payer. But as Democrats have these debates, they should acknowledge that some people — who at this moment in history are largely associated with Bernie Sanders — aren't going to be appeased no matter where the party settles. The folks railing against all the potential 2020 candidates are a slightly exaggerated version of Bernie himself, in that criticizing the party from the outside is where they find their political identity. There is no group of policy concessions or accommodations that will bring them into the fold. They don't want to be in the fold. They want to stand outside the party and criticize Democrats as establishment sellouts, and they always will. It doesn't matter if the party changes in their direction or not, which means that the argument, at least in some quarters, isn't going to end.
Likewise, Bernie Sanders himself is never going to become a Democrat. As Clinton writes in her book, Sanders "isn't a Democrat — that's not a smear, that's what he says. He didn't get into the race to make sure a Democrat won the White House, he got in to disrupt the Democratic Party." To Sanders' credit, once Clinton was the nominee he supported and campaigned for her, but she's right that his primary goal was about his revolution, not about winning the White House for a party he has steadfastly refused to join. Sanders will always be an outsider; that's who he is and how he likes it.
Nevertheless, even more establishment-minded Democrats might believe that these are good arguments to have right now, if they'll produce a party with more clarity about itself (and perhaps one that has moved to the left). The trap to avoid is to write off potential party leaders who have evolved in the ways activists demand for lacking "authenticity." First of all, there's no such thing as an "authentic" politician. They all enact a performance when they're in public; it's just that some performances are more convincing than others.
Second, if you're asking whether they really, truly believe the positions they're taking or are only taking them because they've been pressured into doing so, you're asking the wrong question. Because after all, getting politicians to change is the whole purpose of political pressure. If a candidate who had been wavering on something like universal health care comes around to your position, you should celebrate — your pressure worked!
Sanders may or may not run in 2020, but if he does, his candidacy will likely be nothing like the phenomenon it was in 2016, when he had almost no competition as the one alternative to the seemingly inevitable nominee, and he could be embraced by a portion of the grassroots as the new and exciting thing. In 2020 there will be a dozen Democrats running, almost all of them new to most voters, and they won't offer the natural contrast to Sanders that Clinton did. Democrats are going to have lots of options.
Right now those candidates are watching these debates closely, whether it's about health care or the party's economic message or foreign policy or exactly how it should fight the Trump administration. They want to figure out where they need to move, who they need to appeal to, and how they can craft their own runs to avoid the pitfalls of the past. That's one reason why the policy and political debates Democrats are having right now — even if they get a little heated at times — serve such an important function. The next Democratic nominee, who may wind up shaping the party's identity to the same degree Bill Clinton and Barack Obama did, is him- or herself being profoundly affected by what's happening right now. For that reason alone, Democrats should go ahead and argue.