It is part of the Republican's ongoing battle to stem/reverse demographic and cultural changes and protect their white, male, christian (only certain types), and straight political and economic control.
This recent attempt (one of many over our history) started pre-Trump with a combination of fits/starts - Gingrich's Contract with America, right wing talk radio, alt right media, white supremacists, religious right evangelical groups and conspiracy theorists who finally found the perfect vessel in Trump to help them bring these outrageous fantasies to life.
Stacking the courts, attempting to manipulate the Census, using legislation to punish blue states, gerry mandering on a grand scale, smearing the levers of law enforcement and intelligence (FBI, DOJ, normal media, courts etc.), demonizing religions outside of Christianity especially Islam, fighting against women's rights and the MeToo movement, attacking LGBTQ rights, restricting people of color from exercising their voting rights, creating an anti-immigrant frenzy to keep their base on board and grow/leverage right wing media (Fox, Brietbart, Limbaugh, Sinclair, Info Wars, Daily Caller, Gateway Pundit etc.) to amplify their propaganda.
Now, we also know they are willing to work with foreign countries like Russia, Saudi Arabia, UAE, China and other corrupt forces to coordinate messaging and strategies to serve their common goals.
The Nixonian strategy of deny everything & attack everyone vs political opponents is in full force - Trump will need to be defeated at the polls and then hopefully indicted once out of office. But the larger mission will be to convince the Republicans to return to reality and stop trying to deny history. Like climate change, it is going to happen like it or not and we, as a country, need to be focused on preparing ourselves for the future instead of fixating on returning us to some mythical past based on lies. Hopefully, enough American voters understand what the Republicans are up to now and realize our Republic depends on stopping them.