Yeh that's what I meant by being "valid" and I'm seeing it was maybe too vague. Mea Culpa.

Specifically, he ran Repub to appeal to the massive number of Conservatives that just wanna be left alone, all over the country, that outnumber the illusory Democrat numbers. By running as a Repub, this "validated" him in a massive majority of those Conservative people who were/are just fed up with political bullshit and wanted a human wrecking ball to smash things up a bit.