One of the many topics that Pew Research releases polls about is the subject of political party identification (or “party ID”). Every even-numbered year before a national election, you can count on them surveying on that. Party ID is a little different than just counting up the number of people registered with each party in each state, which is also an important measure if you’re looking at a specific state. But “party ID” is more helpful than that. For one thing, a number of states don’t even have registration by party, so you can never pin down a truly national number.
For another thing, it also lets us know how independents really line up (and for that matter, Ds and Rs line up). Pew’s party ID survey asks people whether they identify as Democratic, Republican, or independent, which potentially skirts around a problem that we saw in the special election in Pennsylvania’s 18th district: the one of “ancestrally Democratic” (or “ancestrally Republican”) areas where people tend to cling to their registration for the once-dominant party (in PA-18’s case, the Democrats) while usually voting for the other party in general elections.
Pew also asks independents whether they lean to one party or the other, which is important because most independents aren’t truly independent; in some cases, they’re better partisans than party members (in other words, they choose to be “independent” because their preferred party is too impure or too feckless, but they’d certainly never vote for the other party; their choice is voting for one party or staying home). The pool of “swing voters,” who’ll freely pick and choose between both parties based on candidates’ individual merits, is actually fairly small.
The main story from Pew’s 2018 survey—and, as you can probably guess, it is very good news—is that Democratic party identification, if you include leaners, is rapidly increasing. The topline tells us that independents are the group that’s gaining the most, at the Republicans’ expense. The nation’s current breakdown is 37 percent independent, 33 percent Democratic, and 26 percent Republican, which sees I’s up and Rs down from when the series started in 1994 (when it was 33D, 33R, and 30I). But when you push leaners, there’s a sizable Democratic edge: 50 Democratic, 42 Republican (compared with 46 R, 44 D in 1994). That’s a large gap by historical standards, though not quite as large as what we saw in 2008 (when it was 51 D, 39 R), when the Democrats won a pretty decisive victory. The gaps are even larger when you start prying the numbers apart by different demographic categories, which we’ll explore further.