It has been more than 15 years since I gave up on American conservatism, but since it represented a big change in my (at that time young) life I still remember much of the process quite clearly. Two things in particular were the deciding factors for me. One, I watched the Southern wing of the party slowly become dominant and it made no sense to me why anyone would take policy cues from and submit to the leadership of people representing the absolute worst parts of the country. "Do we really want to make the country more like Mississippi? Why?" was a question I asked a lot and never got a satisfactory answer. The second tipping point (Is it possible to have two of those?) was the realization that the American definition of conservatism is like the American definition of mayonnaise – it would not be recognized as such anywhere else in the world. American conservatives are not conservatives. Their ideology is better described as either nationalism, anti-government-ism, or some combination of the two.
The fundamental principle of conservatism in political history is, in my view, the defense of the institutions of government (or, as some people argue more expansively, society as a whole). This implies the utmost respect for the rule of law and the constitutional process. Republicans, however, gave up any pretense of that during the 80s and 90s. While I would never describe myself as a conservative (because people would interpret that incorrectly), I still believe that adherence to the power-sharing arrangements of our system of government takes precedence over anything else in the political arena. Without that foundation, we have a system of majority rule that is wide open to manipulation and abuse of power.
Defense of political institutions is necessary because without it, people lose sight of the necessity of the same. When faith in the institutions of government disappears, people are seduced by all manner of nonsense in its place. They might even, hypothetically, react favorably to authoritarian appeals to give one individual the power to act as he pleases without the constraints of any rules or institutional checks and balances. What we see today is nothing more than the logical end result of forty years of telling people that government is evil, rotten, and the obstacle between America and Greatness. How many times can people be told that government is the problem in their lives before they conclude that it serves no purpose that they can see?
American conservatives gave up long ago on defending our institutions. If the Supreme Court makes a decision they don't like, they shit all over the Supreme Court. If the president is not a Republican, they slander him as illegitimate. Any law they do not author is a direct attack on the Republic and its humble, freedom-loving citizens. If they do not win an election, then the election was rigged. Is any of this sounding familiar? Somehow the American left became better at the traditional role of conservatives than conservatives themselves. Al Gore had to be the one to go on TV in 2000 and tell the country that we are obligated to respect decisions of our institutions even when they are obviously riddled with problems.
The Republicans have been living dangerously with their new, nihilistic take on the role of government for years. Despite constant references to their love of the Constitution, they've encouraged Americans to look the other way for the sake of advancing their own agenda. But now it appears that the mood they cultivated has gotten out of their control and they've no longer control their own party. They've been taken over by a con man / publicity hound who doesn't even want to do the job he was elected for. Republicans needed to hawk the importance of the rule of law just enough to maintain control of the institutions they used to acquire or maintain power. But they pushed it too far, like the thief who keeps coming back for one last big heist over and over until he ends up in cuffs. "I should have walked away when I had the chance" summarizes what a lot of Republicans must be feeling today, even if they don't verbalize it and on paper they control all of the levers of governing. They know now that what they have are majorities, not control.
Now the Republican Party is under the control of someone who doesn't even pay lip service to institutions and the rule of law, which is the final nail in the coffin of any meaningful claim to the term "conservative." Token shows of backbone during the election have been replaced by a parade of Republicans into audiences with their new master, groveling for favor and a whiff of the spoils. It isn't the racism and nationalism that means that the GOP is now officially an authoritarian movement; the giveaway is the eagerness with which they embrace government by Big Man, not to be inconvenienced by anything as insignificant as the rule of law getting between America and greatness.