Conversely, what would the EU do if that same request came from another nation instead of the USA? What about Brazil, Japan, China?
It's rarely talked about, but you gotta imagine, the fact the US controls most of the land and sea is a big factor in how diplomatic issues are resolved.
I don't think this is a great thing, btw.
They do so with the help of allies which they seem to forget.
In the 80s USA sent troops in italy to kidnap a terrorist that had surrendered himself to italy. They had to call up all the available carabinieri on the island to counter the USA troops.
Not one has in mind with "allied nation".
https://www.icij.org/investigations/collateraldamage/clerics...
That's been declining: 430,000 US troops in Europe in the '50s, and about 60,000 at the beginning of this year.
That’s been increasing, up to over 100,000 in June of this year.
https://www.defense.gov/News/Releases/Release/Article/307805...
We are talking about a sub-set of security instruments and preventions, one of the many available, are we sure that an armed conflict - or just threat - would worth the trouble?
The answer to all these questions would be hard "No.", possibly followed by sanctions for even daring to ask them.