As an American, I've mixed feelings.

On the one hand, I think I think Europe owning it's own defense would be a solid move to ensure it's own sovereignty and independence as a modern nation.....thing.

On the other hand, I fear this could lead to US - EU military rivalry. While not necessarily the strongest bond in the world, I do value the relatively positive relationship the US and EU have. I hope that bond is preserved and hope we can grow even closer over time.