The most significant military assistance that Europe receives from the US comes through the network of US bases throughout the Continent.
Because of those bases, many of the European security problems of the past two centuries have disappeared. Britain no longer has to worry about a united Continent attacking them, as happened under Napoleon and the Nazis. Germany is no longer concerned about being a major power surrounded on all sides by potential enemies. And the entire continent is protected from expanding external powers, such as the USSR during the Cold War and the early Arab and Ottoman Empires.
Because of those bases, many of the European security problems of the past two centuries have disappeared. Britain no longer has to worry about a united Continent attacking them, as happened under Napoleon and the Nazis. Germany is no longer concerned about being a major power surrounded on all sides by potential enemies. And the entire continent is protected from expanding external powers, such as the USSR during the Cold War and the early Arab and Ottoman Empires.