https://www.newyorker.com/magazine/2006/08/07/the-ic-factor
Theres no great mystery about the motives behind this deliberate misnaming. Democrat Party is a slur, or intended to bea handy way to express contempt. Aesthetic judgments are subjective, of course, but Democrat Party is jarring verging on ugly. It fairly screams rat. At a slightly higher level of sophistication, its an attempt to deny the enemy the positive connotations of its chosen appellation. During the Cold War, many people bridled at obvious misnomers like German Democratic Republic, and perhaps there are some members of the Republican Party (which, come to think of it, has been drifting toward monarchism of late) who genuinely regard the Democratic Party as undemocratic. Perhaps there are some who hope to induce it to go out of existence by refusing to call it by its name, à la terming Israel the Zionist entity. And no doubt there are plenty of others who say Democrat Party just to needle the other side while signaling solidarity with their ownthe partisan equivalent of flashing a gang sign. --snip--
The job of politicians, however, is different, and among those of the Republican persuasion Democrat Party is now nearly universal. This is partly the work of Newt Gingrich, the nominal author of the notorious 1990 memo Language: A Key Mechanism of Control, and his Contract with America pollster, Frank Luntz, the Johnny Appleseed of such linguistic innovations as death tax for estate tax and personal accounts for Social Security privatization. Luntz, who road-tested the adjectival use of Democrat with a focus group in 2001, has concluded that the only people who really dislike it are highly partisan adherents of thehow you say?Democratic Party. Those two letters actually do matter, Luntz said the other day. He added that he recently finished writing a bookits entitled Words That Workand has been diligently going through the galley proofs taking out the hundreds of ics that his copy editor, one of those partisan Dems, had stuck in.