Are Democrats capable of losing under any cirstances?

considering that they havent won a majority in a national election since 1964 (11 mos after Kennedy was shot..... before that being Truman in '48.... while Kennedy, Carter, Clinton 92 & 96 never got higher than 49%); mediocre candidates with mediocre victories seems to be their m.o...... or maybe theyll have another spectacular failure ( kind of like 52,56,68,72,80,84,88, and 04)