[Lower Deck]

He never said he would not defend his NATO allies - read in context he was just really putting weight on the importance of paying their fair share.

Actually he did. He said he would come to a country's defense only they had, in his opinion, "have fulfilled their obligations to us." If he judges that they haven't then he's pretty frank that the support wouldn't be there.

[Eurotwit]

There doesn’t seem to be any “no” there:

“HABERMAN: And if not?

TRUMP: Well, I’m not saying if not. I’m saying, right now there are many countries that have not fulfilled their obligations to us.”