Dan Balz in WaPo:

It’s been called a hostile takeover of the Republican Party, but there’s little that has happened since Donald Trump became the GOP’s presumptive nominee to suggest he wants anything to do with the party. He’s borrowing the brand for his own purposes.

In all ways, Trump continues to show that he is the anti-conventions candidate. That’s especially the case with any notions of him becoming the leader of a political party. Trump is a singular politician unlike any who has risen as fast and as far as he has in modern times. In the same way that he has demonstrated no consistency in his views on issues over time, there is nothing to suggest that he has much regard for the responsibilities and opportunities that come with being the leader of a party.