Some games are indeed zero sum, some are positive and some are negative.
You could also see that in a positive light : Europeans might get a better armies / defence in 10 years compared to if the USA continued its past behavior without Trump
Larger armies are negative sum for everyone. Historically, per capita GDP was flat until the 18th century, because wealth was measured in gold and people thought the best way to be rich was to keep robbing and colonizing one another.
You could also see that in a positive light : Europeans might get a better armies / defence in 10 years compared to if the USA continued its past behavior without Trump