Surely you can think of some cases in your political life where you had to choose between a bad and a worse option?

Simple things, like voting strategically for the least bad of two options in FPTP voting systems, even if the candidate isn't perfect. Like voting for Lincoln (racist white supremacist) over Douglas (enslaver).

Promoting and voting for the best candidate possible who is likely to win their election, even when they aren't as good as you wish they were.