No.
Europe will be at each other's throats the moment the US decides to leave them to their own devices.
Americans have learned to control their violent tendencies mostly. Europeans have not and once they get pushed by the people they hate most in the world, their neighbors, go guano crazy.
Yep. Wait till we leave and the Western and Central European nuclear arms race begins. The only positive that NATO has contributed the last thirty years is keeping Germany non nuclear.