To be exact, Republicans decided to “run” Reagan in 1980. He was already a given in 1984 as the incumbent.
He lost 6 states (and District of Corruption) against Carter in 1980.
Those were truly the good old days, when a bad economy meant a new POTUS at election time.
Now with all the fake money handouts, Baraq won re-election with $4 gas, 8% unemployment (13% actual), surging food prices and trillion dollar deficits.