Marriage equality is in some respects the best example.
If you trace the long arc of the Democratic Party’s slow, steady embrace of LGBTQ equality as a cause, then Biden is clearly right there on the journey with everyone else. At a critical moment, he actually led the stampede, as the first Obama administration official to openly embrace marriage equality during the great Obama flip-flop of 2012.
But back in 1996, as a senator, he voted for the viciously discriminatory Defense of Marriage Act. This was, at the time, a totally unremarkable vote — virtually everyone in Congress voted for it. LGBTQ rights groups didn’t like DOMA one bit, but it wasn’t a litmus test at the time. The state of LGBTQ politics in the late 1990s was that Bill Clinton was trying to make history by appointing an openly gay man to be ambassador to Luxembourg and Republicans were blocking him.
Biden has, in recent years, been a champion of criminal justice reform just like most Democrats. But in earlier years, when most Democrats were “tough on crime” drug warriors, Biden was a “tough on crime” drug warrior who as a senior member of the Judiciary Committee authored a number of harsh anti-drug laws.
It would be a mistake to see him as some kind of carceral maniac, warmonger, or anti-gay bigot — he was a normal Democrat who had normal Democratic Party positions on a variety of issues over time.