Sometimes you can spur the thought processes by one upping them. They want a minimum wage of $20/hour, say you can’t live on that, it has to be $50/hour.
They want single payer health care, you agree and say that the government should provide a car and a 3 BR home to everyone as well.
They want to ban fossil fuels, you agree and counter that the government should ban automobiles and make everyone move to a city where they can walk or bike.
Sometimes a real crazy person will agree with you, but usually they will say that’s going to far. Then you say, how far is too far and who’s to decide that?
I do this one all the time. When they say they want a minimum wage of $15/hr, I say, "Why not make it $50/hr? If $15 is good, then $50 should be better, right?" Then I sit back and enjoy the stupid looks on their faces. Deep down, they know there has to be something wrong with what I just said, but they cannot for the life of them figure out what it is.
Sounds like a fun debate tactic - just take their policy desires to their logical conclusions (ie, the real goals),
and see if they defend them.
That is no doubt the best way to talk to idiots but sometimes I forget that I am talking to idiots and address them as if they actually had a thought process. That is my grievious error. One of my favorite memories is when a full blown liberal clown who steadfastly denied being one made some ridiculous remark and when I disagreed with it he came back with, “There is no one as blind as someone who refuses to see.” I immediately answered him with, “Then why don’t you see instead of refusing?” To my surprise he actually complimented me on the speed of my “turnaround”. He seemed to admire the art of turning his own rhetoric back against him.