Bingo, and this forum has more than a few. Reagan, before he was elected, often said "A country that cannot control its borders, is not a country." Something happened to change his mind on this.
Maybe it was the same leadership that forced him to accept George Sr. as his VP. I remember the convention well, there was no clear choice for VP and the battle raged on til the wee hours, finally RR came to the floor and endorsed Bush Sr.
Maybe I am just a one issue radical, but we could use an Eisenhower about now.
Actually the rumor that night was that Reagan's running mate was going to be Gerald Ford. Reagan then came in and addressed delgates saying it was GWHB to quash those rumors.
You are also right about the 1980 convention: in retrospect, Reagan's appointment of Bush Sr as his running mate was the greatest mistake he ever made.