It’s not about voting for the lesser evil, but against the worse one. The way the United States is structured, which influences the way its people think about voting and vice versa, you are given only two options when voting for president:

• Vote for the Democrat one
• Vote for the Republican one

But… you might think you’re clever and say “I should just vote for neither of them, nobody will stop me”. If your state has RCV then put your preferred candidate as a first pick and just place Democrat before Republican. Problem solved, no more strategic voting. Unfortunately, precious few states have adopted this for any elections, let alone the presidency.

In states without RCV, there are 3 equivalent cases from your perspective:

• Vote Republican: Increment their number by 1
  • Overall effect +1 for Republicans
• Vote Democrat: Increment a threatening score by 1, thereby requiring Republicans to gain 1 more vote to win
  • Overall effect -1 for Republicans
• Don’t vote or vote for a non threatening party/candidate
  • Overall effect 0 for Republicans

Forgive me for assuming the reader wants to get Republicans (and Republican aligned Democrats) out of office. In this case, it is your responsibility to vote for the most threatening candidate. It’s a sick trick of game theory, which is why RCV is so important.