Joe Biden's quick response to Stephen Colbert's gaffe dig is undeniably excellent
2:51am PDT - September 5th, 2019 ups - MashableJoe Biden may be one of the front-runners for Democratic candidate, but he's also one of the front-runners when it comes to gaffes. The former vice president makes a lot of them — he's even referred to himself as a 'gaffe machine.' But during his appearance o…