Kim Jong-un of North Korea is not giving up his nuclear arms. The US demanded that Libya's Gaddafi and Iraq's Hussein give up or stop weapon development programs and then later helped their enemies kill them. Kim Jong-un isn't about to trust the US and will keep his nuclear arms in order to keep the US at (nuclear) arms length. If he gives it any thought - and it seems he has - he never give up the nuclear arms that force the US to take him seriously.
Assuming that Donald Trump is as thoughtful as Kim Jong-un, he won't pass tax reform. Why? Once Republicans have that, they will do far less to resist Mueller's investigation even if that investigation leads to impeachment. Right now the GOP doesn't want to risk losing a rare instance in which they have the House, Senate, and Presidency. At least until they get their very important tax cuts.