"Bush Republican" is a badge worn proudly by many Republicans who came of age after the convulsions of Vietnam and Watergate subsided. If you were with President Gerald R. Ford in his epic struggle with Ronald Reagan in the 1976 Republican primaries, there was a good chance you signed on with George H.W. Bush in the run-up to the 1980 nomination. President Reagan the legend wasn't a legend in those days. "Dutch" and "HW" traded hammer blows as all the other would-be nominees fell away.
As late as April and May, Bush won the Pennsylvania and Michigan primaries, respectively.