Have they ever indicated they might not?  In fact, NATO members, especially the vulnerable eastern members, have provided forces for both Iraq and Afghanistan.  Ever hear of Karbala?  Polish troops are fighting and dying in Afghanistan right now.  They are that committed to NATO.

Ukraine.  True.  However, it has been illegally invaded by Russia, in violation of a direct agreement with the U.S. and U.K.  Their neighbors, to the West are NATO.  The Baltic states face a real threat of similar asymmetric warfare and, in fact, have actually experienced it on a smaller but very real scale.  

Everybody seems to think Daesh is such a threat.  And, they are.  But our greatest threat is Russia.  How many nuclear weapons does Daesh have?  

Dismissing Ukraine as "not a member of NATO" is both naive and dangerous.

Trump?