So, it's no surprise that in 2019, after #MeToo scandals, several women have come forward to speak about unwelcome contact from Biden.
One said he made her feel uncomfortable, kissing the back of her head. None called the incidents sexual harassment.
The opinions of the people on the receiving end of unwanted contact need to be respected. For a lot of women, it's behaviour they have too often suffered in silence or had to laugh off, in the past. Biden will have to prove he can be more disciplined.
Biden said in a video that he never intended anything inappropriate, adding "I get it" about the need for more awareness on his part. Several other women have spoken in support of him. There's also a significant gap between the allegations against Biden and claims of sexual misconduct made by at least 23 women against President Donald Trump.
Biden's trouble has made some commentators question whether he is the right option for a Democratic Party that has shifted leftwards and is seeking a candidate capable of beating a sitting president. Trump proved in the 2016 Republican primary that he is a formidable campaigner. Should the Democrats go for a new generation candidate rather than a Trump contemporary in Biden or Senator Bernie Sanders?
Going by history, being the incumbent is a huge advantage for Trump. Competing as a former vice-president instantly levels the status and experience gap and provides the clearest comparison to the person in the top job.
Biden is easily the Democrats' most experienced, mainstream option, with appeal to independents and moderate Republicans. Of the alternatives, Sanders has a good organisation and voter enthusiasm. Senator Elizabeth Warren has an impressive policy portfolio. Senator Kamala Harris, former congressman Beto O'Rourke and mayor Pete Buttigieg are showing star power.
But in an election where questions over the President's fitness for office will loom large, Biden would provide strong contrasts to Trump.
Biden's ability to connect could become a strength again, should he make it through to the general election.