[DiogenesKynikos]

US GDP is only about 30% larger than EU GDP in nominal terms, which is not enough to matter in this discussion. It's "on par" for all intents and purposes. The EU has plenty of ways to hurt the US economy very severely.

[graemep]

The EU is not necessarily the right comparator. If it came to that level of conflict its possible that not all EU countries would side against the US, its also possible some non EU countries would. However, i agree with your broad point that some European alliance is roughly comparable to the US.

However:

1. European countries are low growth and therefore of diminishing economic importance. Every year that goes by North America and Asia and other economies become comparatively larger.

2. What the US supplies Europe is going to do greater immediate damage to Europe than what Europe supplies the US. The US can turn off things that start hurting economically broadly and immediately and are hard to replace: cloud services, payment systems, etc. Things that only hurt when stocks run out, or that could be bought from elsewhere have less impact.