Yes, it certainly developed over time from Regan-era conservatism. Conservative family values are inherently a rejection of modernity (Eco’s second property of fascism), and the party was already othering people of color and the queer community. The Bush era also did a lot of work priming conservatives for fascism with war propaganda, xenophobia, and equating dissent with treason. Trump brought the party into full-fledged fascism, but it had been stewing for a while before he arrived.