"So is America's."
Moreso than Europe's.
The US is intentionally withdrawing itself from its position as leader of the west, and the preeminent influencer across the globe. So what does that mean? First, the US will cede it's influence in Africa and South America to the Russians and Chinese. "Thank you", says China and Russia. And iran too. As a receding power, the US will negotiate from a position of relative weakness. Columbia and Mexico are going to be less interested in pleasing the US once the US is no longer the leader of the western world. Tariffs, if they go through, are going to limit US companies ability to operate competitively in foreign markets. Now, instead of having a global marketplace, you're limited to what you can sell to customers in the US. I have an Amazon.de account. That will be gone when anything I purchase is going to be n% higher than if I bought it from a European retailer. Even defense, which has been one of the primary methods by which the US has been able to spread influence, could fade. Most of the NATO countries are buying F-35s made in the US, but that means that they are reliant on the US for parts and service support for those aircraft. What if Europe were to come into a conflict, and the US elected to withhold those parts and services? The two absolute worst cases would be the collapse of the dollar as the global trading currency. Every USan benefits from the fact that the vast majority of global financial transactions are indexed in dollars. When another currency replaces it, the US dollar will inevitably indexed to some other currency. My guess would be the EURO. The second worst case would be European countries developing nuclear weapons. Since the end of WWII, the US has provided strategic nuclear deterrence for European partners. This was done in large part to limit the development of nuclear weapons in places like Europe, South Korea, and Japan. Without having a reliable partner to provide that defense, I think Europe would being to question that position. Especially those in the east that the revanchists want to swallow up.
For Europe, this is an opportunity. Europe is at an inflection point, where the EU and partners could work to fill in those vacancies left by the departure of the US. It will almost certainly require rebalancing domestic priorities, but the success of that is dependent really on what the citizens of those European states want.
"Taxing the rich so that society can function well seems like a much needed idea."
The rich are already taxed. Why not tax those who aren't being taxed?
Can you name me a European country where taxes on lower income earners are less than what they are in the US?