Well, it could've been, because, ironically, the guy who was forced out of running for another term, mostly due to a horrific late-night performance at the first presidential debate ... didn't even start speaking to the Democratic National Convention until after 10 PM in Chicago.

Biden's speech, coming on the first night of the DNC, was -- as expected -- a scathing attack on Donald Trump, a firm endorsement of his VP Kamala Harris' presidential campaign ... and also his swan song from American politics.

But, the Dems loaded up the United Center stage with speaker after speaker before Biden was able to begin his headliner speech at about 10:15 PM CT. Back when he was still running for president, we'd reported ... Biden's team didn't want the 81-year-old working or making appearances after 8 PM.

That curfew was out the window last night ... as he only took the stage after a tear-jerker intro from his daughter Ashley's intro and a nearly 5-minute-long standing ovation from the partisan DNC crowd.

Near the end of his roughly 50-minute speech -- it was after midnight on the East Coast when he ended -- Biden pointed out he'd gone from being too young to be a U.S. Senator, having been elected when he was 29, to being told he's too old to continue being president.

Afterward, he was joined on stage by First Lady Jill Biden, Harris and Second Gentleman Doug Emhoff ... and all of his children and grandchildren.