The Democrats should OFFICIALLY declare the Republican Party dead, and only refer to the MAGA Party from now on. Do an actual press conference, and make an official announcement - the Republican Party no longer exists, and has been replaced by the MAGA Party. That will make the traditional Republicans absolutely crazy, and the Dems should keep it up.
Never use the word Republican ever again, refer only to the MAGA, or MAGA Nazi Party. On talk shows, interviews, sound bites, fundraising texts, etc., use the term MAGA Party exclusively. When asked about it, simply say casually and matter-of-factly "The Republican Party is dead, they are the MAGA Party from now on," and leave it at that. Make the MAGAs cry.
