[alex_young]

Since 1955: The Korean war was never ended, and there was an active and continued military engagement with daily exchanges in Iraq from 1991 through 2003.

The mainland United States has not been attacked as a part of a military operation in the modern era, so the defensive claim is questionable.

[zaarn]

I pulled the list from the internet, it was probably incomplete. I sadly can't amend it anymore. The defensive claim is from the source I used.