Well there are extremists in the sense sharing conspiracies of space lasers from a cabal of Jewish people and there is extremism in the sense of wanting to change the healthcare system or believing that genocide is bad even when our allies do it.
Odd hypothetical...If Biden resigns now and Kamala becomes president who would be veep? I assumed it's Speaker Johnson, but she actually gets to choose her VP since he's only in line for Presidential Succession. But her choice has to be confirmed by Congress, and they can block her appointment until after elections. We'd then have months without a Vice President. Not a yuge loss, but it'd feel like driving the family car without some hubcaps, busted wipers and a dead tail light.
It would remain vacant until her nominee for VP is confirmed by a majority of both the House and Senate.