Jay Cost, prize student of the history of American political coalitions, writes (among other things), the following:

Facing the liberalism of today’s Democratic party, all factions of the GOP can usually agree on quite a lot. Virtually nobody in the coalition supports the Democrats’ efforts to increase taxes or federal regulations, especially when the beneficiaries are labor unions or the environmentalist left. Yet that unity can mask a historical irony: The rise of the modern left has pushed many of the country’s old political disagreements into the GOP. The skeptics of big government might once have been Democrats in the mold of Thomas Jefferson and Andrew Jackson, but now they are joined with the heirs of Alexander Hamilton and Henry Clay, who prefer to use the power of government to promote the private economy.

Considering how hot the conflict burned between these two forces when they were in different parties—the elections of 1800 and 1832 were particularly vitriolic—it is little wonder that today’s Republican establishment and its voting base can seem to hate each other more than they do the Democrats. Yet both sides must confront a stark reality: The American left is so strong today that neither half of the Republican party can do without the other.

The GOP has poached most of the conservative voters of the Democratic party. Those who remain committed to the liberal program are so numerous that the Democrats’ share of the vote is unlikely to fall below 45 percent, barring realignment. A united GOP, similarly, can count on about 45 percent support, meaning that politics today hinges on winning the support of that disengaged and unaffiliated middle 10 percent of the country.

Among those who would currently be identified in the “libertarian” wing of the party there are those who are, simply, advocating for their preferred view on these matters.  But there are others, those who cry “RINO!” or “Ogre!” or complain about “voting for what you don’t want,” or talk blithely of how unimportant winning is.  They tend to be either impatient or don’t do well with ambiguity.  (This tendency isn’t limited to the libertarian wing, but I tend to see more of it from there.  Bret Stephens’s recent column about Rand Paul is one example from the other side.)

There are others singing a siren song of purity, sometimes from outside the party, sometimes from inside.  By focusing on disagreements, they would have others believe that Mitch McConnell has more in common with Barack Obama than with Ronald Reagan.  (Come the fall of next year, they’ll be saying the same thing about Scott Walker.)  Drawing sharp distinctions, using the old political sleight of hand that 99 is no better than 0, is useful if you’re drawing a line where more people are on your side than the other.  Democrats do that, to keep the race-based portion of their coalition in line, by pretending that since personal color-blindness is impossible, the only alternative is to write race-obsession into law.

I don’t see much utility when it’s the difference between leading a party of 25% of the electorate and leading one of 45%.  Of course, if you’re interested in “influencing” without the responsibility of governing, that might have some appeal; don’t count on too many people staying around more than a cycle for that party.

There are plenty of disagreements and frustrations within the Republican party.  There are too many Republicans who aren’t willing to roll back the errors of the Left, and others who have compounded those errors with unforced errors of their own.  But the main difference – between the grassroots and the establishment – goes back to the party’s origins. It’s reasonable to take the current Democrat party at its word, that it represents ideas meant to fundamentally transform America away from its founding ideas. As Cost writes, the internal debate within the Republican mirrors many of the historical divisions within the country as a whole.

Pretending that Henry Clay has more in common with Karl Marx than George Washington isn’t a route to being trusted with government.