Ukraine

The GOP has becoming increasingly authoritarian since 2009, when a black man dared to win the presidency and a third of the country lost their ever-loving goddamn minds. The GOP seized on the opportunity to absorb these disaffected racists by leaning into what they liked - unsurprisingly, disaffected racists are typically low-information voters as well, and low-information voters tend to be both easily swayed by flashy propaganda (like, say, Fox News and other 'infotainment') and resentful towards candidates which posit complex solutions to ongoing issues (ie they generally prefer candidates promising easy solutions and 'strongman' style rhetoric). The party then shifted to suit these new and very loyal voters.

As such, the GOP has leaned more and more into a (sometimes explicitly) anti-democratic viewpoint that even neocons have started to balk at. Putin's Russia looks like what they want America to look like - a few people at the top getting very wealthy (what the GOP elite want), and minorities kept 'in their place' and a vain strongman putting on a circus of showing off how very powerful and totally secure he is (what the GOP's absorbed voters want).

It goes much deeper than this, of course. There are other causes and problems, but that, I think, is most core to it.