Decided to make a quick 2016 mockup where Joe Biden is the Democratic Nominee. Based the results on both polling which asked about a Biden v. Trump matchup, as well as on Hillary's peak polling average (D+7) post Access Hollywood. While we have 2020 to go off of, where Biden won but underperformed his expected polling, I do think 2016 Biden absolutely sweeps 2016 Trump (even if he probably still underperforms in the polls), taking a majority of the Bernie-Trump and Obama-Trump voters which Hillary Lost, alongside a significant portion of the voters who either didn't vote or voted 3rd party in 2016 because they just personally disliked both Hillary and Trump.

Focusing on the Senate, the Democrats have their best cycle since 2008, winning 8 seats and regaining control of the senate. This is mainly due to a couple of things. Firstly, Biden has a much higher personal approval rating than Hillary, meaning he doesn't drag down (and probably boosts) the democratic candidates in the Midwest, while at the same time Trump (especially post the debates and Access Hollywood), causes a lot of bleed-off down ballot towards the Republicans. While there is some boost in the Midwest with his ability to turnout populist first time voters, Biden does a way better job in counteracting this than Hillary. Furthermore, Biden also gets a much larger boost being connected to Obama as his VP, with the economy having had significant recovery (especially unemployment) in Obama's final two years as President. Alongside just doing objectively better in the Presidential race, he's able to help senate democrats overperform in the cycle.

Finally, with the House, while we do see the Democrats have a great performance (for much of the same reasons as the senate), they are unable to regain control due to both how gerrymandered the 2016 map was against the Obama coalition, alongside the new Biden coalition not having the large suburban voting base which it would gain post the 2018 midterms IRL.

Finally, just as some extra's:

1. On the gubernatorial side, John R. Gregg in Indiana, Chris Koster in Missouri, and Colin Van Ostern in New Hampshire are all able to win their Gubernatorial races.

2. Post the Election, Donald Trump would attempt to claim that the election was stolen by the Democrats, however the nature of his landslide loss (plus a Republican party which all but predicted his loss) leads to essentially all major political figures in the U.S denouncing him.

3. Another thing that happens post the election is that with the Senate now in Democratic control, McConnell attempts to try and rush through Garlands appointment to try and prevent the incoming Democratic Senate from nominating a more liberal judge. However, Obama quickly rescinds Garlands appointment post the election, giving Biden a supreme court nomination upon taking office. Post-inauguration, Biden chooses to nominate Ketanji Brown Jackson, with her being the first Black Woman to serve on the Supreme Court. (Jackson had been on Obama's original short-list post Scalia's death, and with Biden winning he'd probably want to appoint a justice who both makes history and is a staunch liberal. Also, he probably chooses her as just a big middle finger to McConnell and the Republicans for blocking Garland and screwing themselves over. While one could make the argument that Biden might choose a slightly more moderate judge/keep Garland since he's still entering the Presidency in a divided government, I also think he'd at this point understand that whatever he does, the Republicans are going to attempt to block him as much as possible, so any amount of bargaining would probably not do much. He essentially sees this as being one of the most important things he will do during his presidency and decides to go all the way rather than attempt to moderate.)

Biden 2016