Mike Pence
The question that one should ask is, "Will Mike Pence help win the general election?"
Historically, running mates have very little influence on whether or not the person at the top of the ticket wins, because people usually vote for the top the ticket and running mates are usually chosen without consulting the voters.
In Mike Pence's case, it's quite clear that he will have very little attraction to swing voters. His role seems to be to put a lock on the far right wing of the Republican Party, just to take away the doubts that Donald Trump will adhere to their beliefs.
By picking Pence, Trump has done everything to prevent the Republican Party from expanding electorate. The GOP, is now and for the future, to be considered nothing more than a right wing white people's party.
That autopsy that the Republicans did four years ago after losing is considered to be garbage, I would say. Instead of trying to appeal to women, new citizens and minorities, they have alienated just about everyone except religious, gun toting, xenophobic, right wing white people Nothing's to be learned from it.
So hey, let's do what we've always done, they would say.
Learning from one's mistakes has never been a conservative trait, to say the least.