If you're too young to remember, or just need/want to be reminded, let's review a little recent Democratic party history.
In 1972, our nominee was George McGovern (a man I admittedly volunteered for, although I was too young to vote)...and he lost to Richard Nixon in an OVERWHELMING landslide. (49 states went to Nixon, 1 to McGovern.) So McGovern = LOSER.
In 1988, our nominee was Michael Dukakis, who will forever be remembered for a couple of embarrassing issues, one his doing and the other at the hands of the Republicans. His own faux pas occurred when he (or someone in his camp) had the brilliant idea of putting him in a Challenger tank for a photo op. Unfortunately, this plan backfired, as he came out looking foolish instead of "commander-in-chief"-ish. That would've been bad enough, but once the Republicans took Dukakis to task in the "Willie Horton" issue, it was a lost cause. William Horton was a convicted murderer who was released from prison as a result of a prison furlough program Dukakis supported. Once out of prison, Horton committed a rape and assault, and after this came to light the Republicans grabbed it and wouldn't let go. Dukakis lost to George HW Bush. Dukakis = LOSER.
Last time around, in 2000, our nominee was John Kerry. Although I wasn't crazy about him, I dutifully supported him since ANYONE would be better than George W Bush! Well, the Republicans "swift boated" Kerry and his presidential aspirations ended, too. Kerry = LOSER.
Now what do all of these losers have in common with Obama? They've all endorsed him. Enough said!