If the U.S. were to invade Denmark, Article 5 would not apply. It requires consensus, and the U.S. would never agree to collective action against itself, so any response would be blocked.

Conflicts between NATO members like happened in the past between Greece and Turkey four times, while they were both part of NATO, have never triggered Article 5. The alliance is built to deter external attacks, not wars among its own members.

In practice, after such a move, you can be sure that not a single ASML machine would ever be sold to the U.S. again.