Party-State

 A structure in nominally communist states like the Soviet Union and China is the creation of the party-state, whereby the party controls the apparatus of the state. For instance in China, Xi Xinping is the Party Chairman AND the President, because he is the head of the party and the head of state. For every entity of the state, like the People's Congress, there is a corresponding and controlling party entity like the Party Congress. This is done to retain all the levers of power within the party and render the state as a neutered tool to implement the party's will.

Anyway, Donald Trump's latest purge of the RNC sure shows all the signs of a similar dynamic, but in this case, he is subsuming the Republican Party to his cult of personality and, most likely, criminal enterprises. As Marshall notes, the nominee controls the Party. That's understood. Strategy is coordinated between the presidential candidate and the party committee. The only reason to purge the RNC and install unqualified family members is because you want to use the RNC as an ATM for your hundreds of millions of dollars in fines. 

So there's two ways to see this: the good news and the bad news.

The good news is that if he really follows through and turns the RNC into the ATM, then a few things will happen. First, big money donors will stop giving. They aren't fools. They will give to the RSCC and the RCCC and individual candidates, but many will simply despair and not give. What money does flow into the RNC is extremely unlikely to work well towards electing Republicans. If this fall is as close as it appears to be, that's good news.

The bad news is that the Republican Party is increasingly simply a cipher for Trumpism. At some point, the grip that this demagogic, authoritarian con-man has to be broken. We cannot continue to have every election be a contest between those who respect democracy and those who don't. Sure, at some point Trump will die and that cult of personality will die with him, but the degradation of one of the two parties is deeply troubling.