“Liberalism” does heavy lifting in describing American politics and gets used in incompatible ways. After all, the mainstream of both the Democratic and Republican parties in the 20th century were committed to liberalism. This episode defines “it “liberalism” through what it has done, what it carries, what it is operating in, and what naming it precisely makes possible to see.
“Liberalism” isn’t defined by the Democratic Party, although Democrats are often reproducing a mode of politics that the word names. The word is certainly not defined by the history of “the left.” It also can’t be defined purely through the philosophical tradition of Locke, Mill, and Rawls, even though that tradition set down the frame in the abstract. Liberalism is a governing logic, a political order those ideas produced and stabilized. But it’s also a disposition through which institutions in the West have practiced — and avoided politics for more than two centuries.
The liberal commitment, at its most basic, is that political disagreements get worked out through deliberation, and that decision is legitimate only once agreement has been produced. The pattern produces a specific kind of failure when the people on the other side of a struggle or debate aren’t waiting for consensus. A disposition that requires agreement before acting cannot impose its position on one that requires no such thing. This asymmetry is built into what liberalism has become, in practice. And it’s why American liberals keep losing a conflict they keep mistaking for a contest of messaging and turnout.