If Ronald Reagan is president in 1981-89 and things are roughly the same as they were in OTL, that must mean that even if the anti-third term amendment had not passed, the anti-third term tradition had been revived-i.e., that no president since FDR had sought a third term, and that FDR's having been elected four times was considered an aberration due to World War II. 1988 being a peaceful year, there could be no analogy to that, and the general consensus would be that Reagan should honor that tradition and not seek a third term. He himself would probably feel that way, and Nancy--who was aware that he had started to deteriorate mentally-- certainly would not want him to run again. So I just don't see him running again.