You can have it fast and you can have it good and you can have it cheap. Pick two.
I heard this from a patient on The Good Doctor who said he was in real estate and cited the “pick two” aphorism as a commonplace in his industry. The surgeon responded, “It won’t be cheap.”
It does seem hard, in American politics, to get all three of anything. I remember how positively I responded to Bill Clinton’s line on abortion. “Safe, legal, and rare.”  And I was reminded of that difficulty recently as I see the Democrats casting about for a presidential nominee for 2020. Why is this so hard?
First, it is hard because the animosity between the Bernie faction and the Hillary faction has not yet abated. Some of that animosity appears to be no more than personal grudges projected onto public issues. What could have been a perfectly normal division within the Democratic party between the ideological left and the pragmatic center, got blown out of proportion by the personal attachments of the campaign supporters. Hillary’s people need to get over blaming Bernie’s people for “denying her the election.” Bernie’s people need to get over their resentment of Hillary’s persistent tacking to take advantage of the winds of the campaign season
But down below the personal animosities, there is a true tension within the party. Most of the Democrats I know would really love to be socialists if they thought they could get away with it. If there is going to be a party of the programmatic left, it will be the Democrats. The argument is that Trump will be massively unpopular  by 2020 and that the kind of gains the Johnson administration was able to build on the ashes of the Goldwater failure in 1964 will be available again in the ashes of the Tump failure in 2020. This argument adds to the preference for programmatic left wing reforms, the always seductive, “Now is the time.”
On the other hand, Democrats who are more moderate in their social and economic goals as well as more pragmatic in their political ambitions, urge winning as a first step. First win back the presidency and the Congress, this argument goes, and then we will talk about what to use them for. At the very least, we will be able to begin rolling back the worst of the Trump excesses and as a common core of progressive social goals is agreed upon, we can do them next.
This argument agrees that the Republicans may be very weak in 2020 as a result of the expected Trump implosion but they make the case that winning seats is more important than the success of the programs so dear to the left wing of the party. And you don’t have to say out loud that you don’t share those goals if you can just make the case that it would be risky to pursue them.
This is essentially the dilemma Bill Clinton faced in 1992. He was up against an incumbent president, the heir of the very popular Reagan administration and also up against a radical and unresponsive Democratic left wing. It took him some bare knuckle work, mostly in private, and a lot of reconciliation, mostly in public, to get the party back together.
But that was then. This is now. Clinton was up against George H. W. Bush, who was, whatever you would like to say about his politics, a gentleman. The 2020 Democratic nominee will (probably) be up against Donald Trump, who is engaged in what looks remarkably like an adolescent rebellion. The Democrats cannot oppose Trump the way they opposed Bush.
Furthermore, the tribalization of American politics has progressed much further since Clinton’s time, even since Obama’s time. 2020 is going to require a warrior, not a reconciler. And if he  is not belligerent in the policy sense, he still must be stylistically belligerent; he must be seen as someone who “fights for” his party. He can count on his excesses being forgiven by the members of his party where he could not count on his restraint being forgiven.
And this isn’t as easy as you might think. The Republican party and the Democratic party are not the same kind of thing at all. The dominant voice of the Republican party is now a movement-oriented voice, something like jihad. The Democratic style is collecting groups of voters who are willing to sign on for the campaign, like a state militia. The Democratic party works like the United Nations, not like Al Qaeda. 
If getting belligerent, as I say, above, will be required of him, the Democratic candidate also needs to cultivate the constituent “nations” that make up the party voters. He needs to be seen as a warrior fighting for the interests of each crucial part of the party and to fight for each in a way that makes him acceptable to all. Good luck with that.
So the next Democratic nominee needs to be a programmatic leftist and a pragmatic centrist and a warrior who leads his party against the enemy.
 It’s a phrase worth celebrating. Not only is the rhythm easy to enjoy, but it also distributes the goods nicely. Lefties like “legal;” righties like “rare,” and everybody likes “safe.”
 Not among his core constituency. Nothing will do that. But the Democrats don’t need Trump’s core constituency to win back both the Congress and the White House.
 I’m perfectly capable of using “he” as a neuter pronoun when it doesn’t really matter, but in the case of the Democratic party in 2020, it really does matter. The Democratic candidate in 2020 will certainly be a man and in all likelihood, a white man.
 We commonly refer to Trump’s “base” or “core constituency.” That is actually what the word “al-qaeda” means so there is a very satisfying irony there.