The U.S. doesn't make up for it. The U.S. funds its own armed forces and deploys them as it sees fit. Reduction in European defense spending didn't result in additional U.S. defense spending to make up for it. And an increase in European defense spending wouldn't result in more money for the U.S. armed forces. The two are not related.
“The U.S. doesn’t make up for it.”
The US has been making up for it for decades.