This shouldn't be a big surprise to anyone. Political evangelicals support Republicans, because the Republican platform has the things on it they want. If the Republican platform didn't have those things, they wouldn't endorse. It's a purely transactional relationship -- the words coming out of their mouths are just the packing material you stuff around the goods being shipped in order to keep it from being too damaged during transit. It is, in short, a bribe: the Republican equivalent of the mythical Obamaphone.
The political wing of the evangelical movement can no longer call themselves "evangelical." In a political context, the word means nothing more than "this soul is for hire." It is an empty, hollow shell, willing to sing "Lord, Lord" for a reasonable hourly rate, negotiated in advance.
It is certainly not evangelical in the religious sense--you know, where the word actually came from, meaning people who believe the Great Commission is still in effect today. It isn't the evangelical that makes people sacrifice in order to minister to the lost, either by their own missionary work or by supporting that work.
No... the political wing of the evangelical movement has jumped the leviathan. By endorsing Donald Trump it has shown that the thing it loves first and foremost is the accumulation of political power, and that it will ally with anyone who will promise them that power. It has, finally, exposed its secret idol to the rest of the world.
They worship power. They lust for it. They hunger for it. They hoard it. They are angry when they don't have it, they envy the people who do, and they are proud of what power they've accumulated so far. The only deadly sin they don't have in this respect is sloth -- I'll give them credit for that. They work very hard to sell their souls, each and every day.
(If you are interested in the letter Dobson wrote in 1998, you can read the entire thing here.)