I think this is important because
you get the opponent to accept the logic on the crutch of his own terms
then you remove the crutch, replace it
in the act of pure reason he would then have to change his mind to believe what his emotions want him to believe
insertion of argument that ourguys may use later
https://www.newsweek.com/robert-reich-if-trump-guilty-his-presidency-must-be-annulled-opinion-1092345
http://www.baltimoresun.com/news/opinion/oped/bs-ed-op-0829-reich-annulment-20180828-story.html
An argument is being made (won?) that presidential actions should be annulled in the case that a president proves to have been compromised by a foriegn entity.
Once the argument is won, it's principle can be applied generally.