It'll be ironic if Trump got himself impeached because he was afraid of Biden and Biden ends up not being the Democratic nominee.
Regardless, given the top two tonight were Sanders and Buttigieg I can predict what conservative attack ads will be.
With Sanders it's a no brainer; Republican voters aren't particularly bright and are stuck in a Cold War mentality so they'll just show Bernie in front of a hammer and sickle with Soviet style music playing while warning about the dangers of 'teh ebil socialism!!!'.
Buttigieg will probably be 'If we elect a gay man President, God will turn his back on America!' or something along those lines because conservatives still haven't figured out they've lost on gay rights even with the 180 degree turn Americans views have made towards gay rights in the 16 years since 2004 when it was a successful wedge issue for Bush 2.