I hear a lot of people discussing about the need to choose ‘the lesser evil’.

Otherwise the ‘greater evil will prevail’ they warn us.

I’m afraid that those who fall into this trap actually validate the idea that ‘evil is acceptable’.
Every time this subject comes up I keep remembering the joke about an older man asking a young lady:
‘Would you sleep with me if I gave you a million bucks?’.
‘Well, I’m not that kind of girl… but you know, that’s an awful lot of money… I could help my old parents… I could go back to school… OK…”
‘But what if I gave you $100?’
‘I told you I’m not a hooker!’
‘That’s already been settled. All that’s left for us to do now is to negotiate the price.’
Same thing with ‘choosing the lesser evil’. Once you’ve  accepted that evil is inevitable … you’re sure to get some. And keep getting it until you quit playing their game.
That doesn’t mean we schould quit voting all together. It would send the wrong message. Even if you don’t go to the voting booth because you are disgusted by the available options the ‘analysts’ interpret your stance as ‘they’re so despondent that they don’t care anymore about their own fate. They they don’t have enough energy left in them to protest so no need to change anything. Or, maybe, things might be allowed to become even a little worse. For them, of course.’
What we need to do is vote what we really like, even if that candidate doesn’t stand the slightest chance. This way the intention of the voter is absolutely clear – ‘I want exactly this’.
If there is no acceptable option, we can always check the ‘non of the above’ box – if available – or take the necessary steps to annul your vote – the specifics depend on local rules and regulations. Again, this sends a rather clear message. ‘I refuse to play into your hands and accept that evil is inevitable’.