Pretty much a symbol of failure.

I dont know if he was taken seriously. too liberal in his platform

Typical liberal of his era and nothing special. The Democrats in Minnesota were so bankrupt after Wellstone's death that they dug Mondale out of the closet and put him on the ballot for US Senator. Everyone thought it was super cynical and Norm Coleman cleaned Mondale's clock!

A very good politician who peaked at the wrong time in the wrong place. He never lost a debate until the second debate with Reagan, and the only reason he "lost" that one was the question of one of the panel journalists who asked Reagan if age was an issue and Reagan remarked "I won't make my opponent's youth an issue." That was the headline, and everything else was lost. But one of the few bright spots of Mondale's campaign was the first debate, where he clobbered Reagan but good. Didn't make a huge change in the polls, but the Reagan handlers were in a panic between debates.