While Hillary is busy today explaining the reasons for her loss, it’s worth noting that Democratic strategists have recently come to their own conclusions about why she lost the election. Based on an examination of new data, strategists believe Hillary’s loss was mostly the result of voters who had voted for Obama in the past but jumped party to vote for Trump. From McClatchy:

Many Democrats have a shorthand explanation for Clinton’s defeat: Her base didn’t turn out, Donald Trump’s did and the difference was too much to overcome.

But new information shows that Clinton had a much bigger problem with voters who had supported President Barack Obama in 2012 but backed Trump four years later.

Those Obama-Trump voters, in fact, effectively accounted for more than two-thirds of the reason Clinton lost, according to Matt Canter, a senior vice president of the Democratic political firm Global Strategy Group. In his group’s analysis, about 70 percent of Clinton’s failure to reach Obama’s vote total in 2012 was because she lost these voters.

The difference this makes is enormous. It’s the difference between running a campaign to turn out your base and running a campaign designed to persuade voters who could go either way. The Democratic Party’s left flank has a lot invested in the theory that demographic changes make persuasion unnecessary. If you can simply turn out the Obama coalition of minority groups and progressive whites, there’s no reason to try to persuade anyone on the other side. But if in fact, Hillary lost because she failed to appeal to swing voters then the calculus is different.

Lanae Erickson Hatalsky, a vice president at the center-left Third Way, tells McClatchy, “There’s still a real concern that persuasion is harder and costs more than mobilization, so let’s just triple down on getting out the people who already agree with us.” She adds, “And I think there’s a lot of worry that we don’t actually know how to persuade anymore, and so maybe we should just go talk to the people we agree with.”

That’s a debate which we’ve seen playing out in real time. Just over a week ago the new DNC chairman, Tom Perez, announced that every Democrat must be pro-choice and that anyone who isn’t shouldn’t expect any help from the party. Perez got some pushback from Cardinal Dolan and others who found his view of party loyalty extreme. If the Democratic party could win elections by rallying its base, then Perez’s comments make sense. But if the data shows Democrats still need to appeal to swing voters to win elections, then Perez’s comments only wind up creating a barrier to a large block of potential voters.

Similarly, Perez made news with his comment last month that Republicans, “don’t give a s**t about people.” No doubt that’s exactly what the party’s base wants to hear and serves to keep them worked up. But those comments are not helpful if your future success depends upon winning over voters who decided to go for the Republican in the last election.

In short, the data seems to say that Hillary’s problem was that she didn’t appeal to a lot of people who voted for Obama. But the party leaders are behaving as if all they need to do is please their own base. Canter, the strategist behind the analysis, tells McClatchy, “This idea that Democrats can somehow ignore this constituency and just turn out more of our voters, the math doesn’t work.”