WORCESTER, Mass. — On the night of his election to the Senate in 1976, Daniel Patrick Moynihan, Democrat of New York, declared: “I ran as a liberal. I was elected as a liberal.” This month, discussing her campaign for the Democratic nomination for governor of New York, Cynthia Nixon called for “progressive change.” The distinction matters.

In recent decades, the label “progressive” has been resurrected to replace “liberal,” a once vaunted term so successfully maligned by Republicans that it fell out of use. Both etymologically and ideologically, the switch to “progressive” carries historical freight that augurs poorly for Democrats and for the nation’s polarized politics.

Historical progressivism is an ideology whose American avatars, like Woodrow Wilson, saw progress as the inevitable outcome of human affairs. Of course, liberals and conservatives believe that their policies will result in positive outcomes, too. But it is another thing to say, as American Progressives did, that the contemporary political task was to identify a destination, grip the wheel and depress the accelerator.

The basic premise of liberal politics, by contrast, is the capacity of government to do good, especially in ameliorating economic ills. Nothing structurally impedes compromise between conservatives, who hold that the accumulated wisdom of tradition is a better guide than the hypercharged rationality of the present, and liberals, because both philosophies exist on a spectrum.