As poor of a state that is Europe's various armies, I'd be very surprised if EU couldn't take on Russia even without the US (who FWIW recently reiterated their commitment to the defense of Europe). Russia's advanced SAMs, radars, and Navy have seriously deteriorated. Their main capability left is submarines and mass Shahed drones whose range can't reach much of Europe.

If Russia's jets can't operate over Ukraine they won't do much in Europe except self-defense of their own homeland.

China on the other hand is a very very serious opponent...

GP is talking about the invasion of Ukraine, taking place just beyond the EU eastern border, and very much shaking up the European security situation, and the EU and its member states are visibly having to "deal with it", diplomatically, economically and in terms of their practical defense postures. That's what they meant with "at the border", and not a literal invasion of the EU.

(Edited for a less confrontational beginning of the first sentence.)

As another European: Yes?

Invasion doesn't have to mean they plan to roll tanks all the way to Paris.

Have you realized Russian agents blew up a train in Poland this week, after some weeks prior flying planes and drones into NATO airspace and disrupting air travel in Denmark with drones started from shadow fleet tankers. The grounds for further action are being tested as we speak.

Invasion just means Russian soldiers enter Poland, Latvia, Estonia, Finnland. Countries parts of which Putin painted rightfully Russian territories in his speeches. I wouldn't bet a lot on that not happening, especially if the geopolitical situation deteriorates in favor of Putin.

Yeah it's all very dumb. The rest of Europe is protected by no less then three state nuclear triads. Ukraine was not.