Good article. I've *always* been a conservative by his definition. I have, of course, never ever supported the Republican Party, because it stopped being conservative by that definition before I was *born*.
He's absolutely right that the modern Republicans are the heirs of the slavers who seceded in order to promote slavery.
Worth noting that right-wingers are now writing essays explaining that Kavanuagh is simply unsuited to be a judge, due to his record of lying under oath, his appearance of a conflict of interest and his inability to maintain a judicial demeanor:
I Know Brett Kavanaugh, but I Wouldn’t Confirm Him - The Atlantic
Kavanaugh needs to be impeached immediately. If the Republican fascist party confirms him, it will only confirm that they hate the rule of law and are traitors to the Constitution.
The book
American Nations covers the cultural battle this country has been locked in since before it was a country. In the early days after the Constitution was confirmed, the battle was between the New England Yankee's centered around John Adams and the Tidewater culture from Virginia centered on Thomas Jefferson. The Jeffersonians evolved into the Democrats via a few name changes. The Adams followers first became the Whigs, then the Republicans on the eve of the Civil War.
Over time the focus of the Democratic side shifted to the Deep South as Tidewater became diluted and failed to expand with the other cultures.
The Adams faction favored a strong central government, but also were champions of individual liberties too. They were anti-slavery from the beginning of the country (though there was some slavery in New England during the colonial period). The Democrats were more for a weaker central government with stronger states' rights, but their attitude about civil rights were more a caste system than a meritocracy that the Whigs/Republicans favored.
The entire political history of the US has been about which faction was ascendant and who their allies were. This is a good site for the history of presidential elections (the owner of the site uses blue for Republicans and red for Democrats, but the data is good):
Dave Leip's Atlas of U.S. Presidential Elections
Before the Civil War was less clear, but in the 19th century after the South was a Democratic stronghold and the North Republican with the West largely deciding the election. At the beginning of each of the Party System periods the winning faction put together a new coalition that cemented their power for a generation or more.
FDR pushed the Yankee centered Republicans back to New England, though the interior West started voting Republican before he was done. Eisenhower took every faction but the Deep South, but his coalition was only centered on him and did not become a larger movement.
The Civil Rights movement broke Roosevelt's coalition. It was popular in the North and the West, but deeply hated in the South. The political system cast about with no real rudder through the 70s until Reagan came along and stitched together a new coalition consisting of the Deep South, Appalachia, and the interior West. The old home base for Republicans became the new home base for Democrats: the Northeast.
The personal liberty mantle is now held by the Democrats. The Republicans talk about championing states' rights, but do the opposite when in power.
The coalition stitched together by Reagan is falling apart. They have become so ideologically extreme they can't govern anymore. the problem is the Democrats don't have a seed crystal like Roosevelt or Reagan to form a new coalition and the hatred the Republicans created for anything not Republican starting in the 90s has entrenched people so much, it's going to be difficult to shift to a new coalition.
My father was an Eisenhower Republican for most of my life. Eisenhower was out of office when I was born and died when I was a toddler, but that was the brand of Republicanism my family embraced. The Republicans of that era started the Equal Rights Amendment and were not solely in favor of tax cuts, but instead fiscal responsibility.
When Bush I's tax increases backfired, the Republican strategists decided that all they would talk about is tax cuts from then on. They became maniacal tax cutters with an insane belief that cutting taxes would cure all economic woes in the same vein of thinking that if two ibuprofen help with your headache, the whole bottle must be much better.
Taxes may have been a bit too high in the 70s, and cutting them a bit might have helped stimulate the economy, but there is a sweet spot in there and cutting taxes beyond that just wrecks the budget for no good reason. (Taxes may not have been too high either, but an argument could have been made in 1979 to experiment with cutting taxes a bit and see what happens.)
The religious social conservatives have always been a part of the US mix more than a lot of European countries. Europe expelled a lot of their more extreme religious groups and they came to the US. Some have remained largely apolitical like the Mennonites, but other religious movements, most home grown in the US, did find their political voice in the latest party period. One of Reagan's geniuses was wooing evangelicals into the new coalition. Evangelical Christians did not see themselves as a political faction before that. Before 1980 they politically saw themselves as part of some other group like working class voters or Deep South voters. They were forming a clear identity with the Koch family's Moral Majority movement, but Reagan capitalized it into a full blown faction in the Republican Party.
The Republican Party today is mostly factions created by the Koch family: The John Birchers are mostly lost in the mix now, but the Moral Majority movement coalesced the Evangelical Christians, the Militia Movement coalesced the rabid 2nd Amendment followers, and the Tea Party opened the door for Trumpers. There is a lot of overlap among these people, but all of these astroturf movements created by the Kochs have contributed to the strong attitudes within the Republican Party today.
The Republican Party has become a cult, while the Democratic Party is still casting about for an identity, but actually does want to govern responsibly.