Every single person involved in that investigation should be arrested, charged and prosecuted for treason.

Any employee of the FBI, the DOJ or any other US government agency indicating, implying, intimating, suggesting, inquiring about or in any other way attempting to gather data in such an investigation to prove a President of the United States was a Russian Spy, should be hung at noon naked on the Washington Mall and left dangling in full public view for 2 weeks.

And I adamantly oppose the death penalty, but some crimes are just too much beyond the pale and this one most certainly is.