Here is a simple model to explain why Democrats will unite on social issues but not on class issues.

Suppose you are an ambitious moderate-liberal Democrat who wants to become president. (Thus, I am interested in the national party, as opposed to state parties.) What is the best way to expand your base of supporters?

One strategy would be to try to reconstitute the New Deal coalition. You move to the left on economic issues and to the center on social issues, in the hopes that you could pick up independents and some white working class Republicans. The other strategy would be to remain moderate on economic issues (which means that you are pretty liberal anyway-- after all, you are a Democrat). Instead, you move to the left  (or, in the alternative, become more vocal) on social and identity issues, emphasizing your support for abortion rights, transgender rights, undocumented immigrants, so on.

In some red states, such as my home state of Missouri, the first strategy--move to the left on economics, move to the center on social issues--might be quite effective. But nationally, this approach faces a couple of big problems. First, if you start sounding too much like the Sanders and Warren wing of the party, your wealthy donors will strenuously object. Second, if you move to the center on social issues, the party's socially liberal base will loudly object, and this will sap your support. You may lose more voters than you gain. To be sure, Bill Clinton tried this strategy in 1992, but that was over twenty-five years ago. The composition of the party was quite different, and it’s not clear that it will work nationally today.

So your safest bet to expand your support is the second strategy. You should stay moderately liberal on economics (keeping your wealthiest contributors happy), and you should move to the left on social issues—or at least signal visibly and vocally on these issues.

Now suppose you are part of the Sanders/Warren wing of the party and you want to expand your base of support. You are not going to move to the center on economic issues--you will be regarded as a sellout by the very people who most strongly support you. So your most plausible strategies will involve either moving to the center on social issues or signalling that you are firmly on the left on social issues.

Once again, the second strategy is likely to dominate the first. Move to the center on social issues and the party's social liberals and some members of minority groups will not trust you. As a result, you may lose more voters than you gain. And because your positions on economic issues are so far to the left, your ability to get contributions and support from business-friendly and moderate Democrats and independents will be limited, even if you tack to the center on social issues. As a result, your most likely way of improving your position will come from solidifying support from minority groups and from the party's social liberals. Once again, the path of least resistance is to align yourself firmly with the party's socially liberal views. (Political scientists may recognize this as a stripped-down version of the Miller-Schofield argument, with some slight alterations).

Note how the dominant strategies for moderate Democrats and economically liberal Democrats converge. That means that, for the time being, Democrats may find it easiest to unite around social liberalism but not economic liberalism. In today's Democratic Party, you can be moderately liberal or very liberal on economics. But on social issues you should remain firmly on the left.

A recent story about Joe Biden confirms this intuition. Biden is the natural inheritor of the Clinton/Obama business-friendly wing of the Democratic Party. Under pressure from party activists, Biden quickly and suddenly changed his long-held position on the Hyde Amendment, which prohibits most federal funding for abortions.

This story is not important for the reasons the media covered it—to expose the machinations within the Biden camp, or to remind people that Biden has held many conservative positions in the past (which he has). Rather, the story is important because it symbolizes the balance of incentives for Democratic politicians. 

A moderate liberal like Biden will find it much easier to shift positions on issues of identity and social liberalism than on issues of class and economic inequality. Of course, as he does so, his opponents will try to remind voters of his earlier, more conservative positions on race and other identity issues. But in one important respect Biden won’t care. In fact, he wants to signal as strongly as possible that he has moved to the left on all of these issues. By contrast, I would be very surprised if Biden embraced Elizabeth Warren's positions on economic reform as quickly as he changed his mind on the Hyde Amendment. 

Republicans face a different, but complementary set of incentives. For the time being, it will be very hard for them to move to the center on social issues. They have spent too much time establishing their position in the culture wars for that.  But as the party becomes increasingly identified with white working class voters, there is space for strategic realignment on certain issues of class and economic equality, as long as these issues are not coded as socially liberal or seen as especially benefiting minority groups. Thus, Republican politicians can move to the center on class issues if they support "family-friendly" economic policies that are coded as helping white working-class people. (This requirement-- that the policies offer no hint of redistribution to minorities--should remind you of the problems Democrats faced during the New Deal.)

Republicans can also make populist attacks on Big Tech (whose leaders tend to be liberal Democrats). Republicans can even get behind certain kinds of antitrust reforms to the extent that this can be sold as benefiting white working class voters and not as the federal government regulating the economy.

Senator Josh Hawley of Missouri is currently attempting a version of this strategy. He is signalling that nobody will outflank him to the right on issues of religious freedom, while taking a prominent position on regulating Big Tech. I expect that other ambitious Republicans will attempt variations on the general theme until they find a model that maximizes their potential base of support. What that model will ultimately look like, however, is not foreordained: it will be shaped by many factors, including the views of the party’s powerful donors. Previous attempts at moving to the center or to the left on class issues have been foiled by the donor base--which, as we have seen in the Tea Party and Trump eras, appears to care most about upward redistribution.

In sum, in the new party configuration, the two parties will continue to be opposed on social and identity issues. But both parties are going to have a populist wing and a neo-liberal wing.

Although both parties are internally divided on class, they are most definitely *not* the same on class issues. The Democratic Party, for the foreseeable future, is likely to be far more economically egalitarian than the Republican Party. It is unlikely to abandon its commitments to universal health care, the environment, and other economic issues. But moderate Democrats and the party's donor base will be more conservative than much of the party.

We can tell a complementary story about Republicans. As a result of its successful cultural strategy, the Republican Party has absorbed many economic populists, who, among other things, support Medicare and Social Security. But the party's donor base and its activist networks mean that it is not going to support very liberal economic programs.

Given this configuration, even if the Democratic Party is the dominant party in the new regime, it will be difficult to achieve real change on economic issues with only Democratic votes. The Democrats are now a cosmopolitan party, and not the party of the New Deal.

As strange as it may sound in today's political climate, economic progressives will need help from the other side of the aisle.  If they do not figure out how to do this, the neo-liberal wings of the two parties are likely to set the agenda.

That suggests that real change awaits the end of party polarization. How that comes about is the subject of the next installment.

Posts in this series:

1. Escaping Dysfunction
2. Cycle of Presidents or Cycle of Regimes?
3. How Polarization Leads to Disjunction-- There Must be Fifty Ways to Leave Your Party
4. The New Party Configuration
5. The Limits of a Cosmopolitan Party
6. How Constitutional Rot Ends