Just that when an extreme regime wins power it’s a natural reaction to want the opposition to combat it from the opposite side of the political horse shoe, but because what’s happened is the Overton window has shifted towards the bad end of things you should be prepared to make more compromises in your choice of political leaders than are ideal.
Our American friends here are almost unanimously supporting Sanders or Warren for the Dem candidacy (as am I policy-wise) and seem resolutely against moderate candidates like Buttigieg or Bloomberg because they seem like washouts (which they largely are) and aren’t a strong enough antidote to Trump, when really the situation there is so dire that they should probably get behind whichever candidate they think offers the greatest chance of getting rid of Trump.
cf Thatcher. In hindsight we’d have been better off in 1983 with a centrist Labour leader like Healey/Shore/Jenkins/Owen than the idealistic and popular with party loyalists but low electoral-appeal Foot.
If this all sounds a bit Blairite that’s because it probably is, and there’s not much else I agreed with him about other than the pressing need to bin the Tories.