US has a pretty strong political leverage in most of europe. 1.Believable defence against Russia is built on the existence of Nato and the US forces it brings. 2. I guess there is still a sense of goodwill involved. US funds helped to rebuild europe after ww2 to stopgap Soviet Union. 3. Economic threat (not direct, but latent). 4. Personal reputation. I guess being too anti US is considered a faux pass in various places.