“ Pence was a forced error, like a number of his other appointments.”
Let me revise that. Trump *thought*, or rather was misled into believing, that he couldn’t win without support from the establishment. And the way to win support from the establishment was to pick an establishment running mate like Reagan did in picking H W. As we now know that is not true. Outsider candidates, if their base of support is wide enough and deep enough can run a campaign on their own including picking a running mate of their own choice. This mistake will not be made again. Of course it helps to have the party apparatus on your side, but when you control the flow of money the party apparatus won’t have a choice but be on your side.
Pence wasn’t named to the Trump ticket because he was an establishment guy. He was put on the ticket to give evangelical Christians an assurance that it was OK to vote for Trump.