He didn’t want to give up his last 2 years on the Governorship to the Conservative Democrat Lieutenant Governor. Had he run and won, it’s almost certain that Gore would’ve run for Governor in 1986 and would’ve won (and from that position, almost certainly would’ve ended up as VP in ‘92, as he would’ve been even closer to Clinton). These guys just take different routes to power.
Still, I can’t imagine having had Lamar! as a Senator since 1984. He would’ve eventually become floor party leader and even worse, might’ve been foisted on us as a Presidential candidate (a la Dole) by 1996 or 2000. Blech.