After the disasterous Presidency of Jimmy Carter, the Democrats realize they have a steep, uphill battle ahead of them in the 1980 election.
Liberal Muskie fails to make any breakthrough in the south, dimming his already faint hopes of victory. Glenn helps somewhat with more moderate voters, but this is overshadowed by the far greater appeal that Bush has for this same group.
Bush comes into the campaign well respected for his admirable record of public service, and as a credible Presidential candidate. The presence of Goldwater on the ticket goes a long way in keeping the conservative voters on side, particularily in the south and west. Goldwater by this time is revered in some quarters of the country.
These factors result in a clear and comfortable win for Bush and Goldwater.
Bush/Goldwater 335
Muskie/Glenn 203