Do Germany, France and the UK really look at the current US at their current hegemon?
Is that a rhetorical question? Have you followed any of European security and defense news lately? Of course they do. Let's talk about it.
The Americans have a number of levers by which they exercise, more or less, an unilateral veto over the security policy of those three nations, and which they can pull to remind them just how dependant these nations are on the USA without the USA being dependant on them.
1) Access to intelligence sharing - a real biggie. Sharing is caring? Well, actually, the USA have far greater Intel capabilities, thanks to spy sats, tapped wired, sigint infrastructure and most importantly evaluation capability (manpower). They have so much to share, and the others (except maybe the British and Israelis) don't. Much of the information that the security services in these nations depend on for defense against terror threats and threats to their overseas interests (shipping on the high seas, military forces stationed abroad, etc), they get via "sharing" from their benevolent and much larger partner. Of course the partner shares info selectively. This sharing is dependant on cooperation, which means, the inferior partners do not interfere with American intel gathering in their nations and grant full access to their information infrastructures (something they do not get in return). This includes not resisting even the most intrusive spying like when the Americans wiretap the prime ministers and presidents of these nations. It is well understood that ending cooperation means an end to information sharing, which is a horror scenario to European domestic security services. (Particularly the German ones, many of their successful arrests of domestic wannabe terrorists, and virtually all successful defense against threats to German military troops stationed abroad, are the result of information gained through intel sharing with the Americans.)
2) Military capabilities. Loup99 would argue otherwise, but the accepted paradigm of security strategy nowadays is that the further from your territory your defend against threats (and assert your interests militarily), the better. NATO enforced the end of the Yugoslavian wars, and staved off another potentially very huge refugee wave into western Europe, with the Kosovo intervention in 98/99. This war could not have been fought successfully without the American Air force. Not just because of sheer numbers, but also because of the capabilities that the Americans bring to a campaign: Aerial refueling, counter electronic warfare, and of course their unrivaled reconnaissance and intel gathering capabilities. The Kosovo war was won, by NATO, and couldn't have been won, without the USA. Since then, the defense of European interests has taken on a very forward oriented character. We are in Mali defending some allies of the French against islamists insurgents, we are off the horn of Africa defending our shipping against pirates, we (well, not Germany) went into Libya and intervened in a civil war in order to overthrow Gaddafi's government which had (again) turned hostile to shared European interests. Currently the Europeans are scratching their heads thinking about what to do if the Russians escalate a military (or electronic warfare / cyber sabotage) threat against the Ukraine, or the Baltic EU members. And in all these cases, the military planners pretty much agree that it's going to be a dismal effort if the Americans aren't on board. Guess how this affects the European outlook. The Americans are indispensable, and you cannot make major security policy moves without first asking them, and getting their green light and support. In military procurement, which is very close to the heart of security politics, it is difficult to deny the Americans a role that they desire, if they insinuate that the consequence will be reduced access to American military hardware. Why do German government satellites launch on SpaceX rockets, and not Ariane rockets? Because the German security services wanted to accumulate valuable brownie points with the American friends, and the politicians who decide on these topics and usually try to look out for European shared interests (like ESA which totally is a shared interest) felt they needed the brownie points more than they needed to stick to common euro interests. Why is the EU's military initiative that aimed to increase strategic independence going nowhere? Because a number of member states feared the consequences of losing American favor so much that they insisted the Americans must be part of this originally EU-only initiative.
Now, an American who isn't very familiar with European policy could say, well Jodel, those things you list, that's all part of a voluntary relationship! We aren't the bad guys here? We're paying for your security! Grow some balls, Euros, and then we can pull out and leave you happy on your own, no problem! And the American would be right. In a way. But at the same time, the fact that its a relationship in which the Europeans are kind of voluntarily the lesser partner by far, doesn't change that they are utterly dependant and that any moves away from "cooperation" and "always ask the Americans first" would still entail consequences (from the American side) that would substantially diminish those nations' security situation. You don't want more terror, you don't want to be left alone with the Russians, you don't want to be on the angry side of the Americans and their fearsome cyber capabilities. And then there's the aspect of financial hegemony, separate but close to security issues ('close' from the EU's and especially Germany's and Italy's point of view) that I didn't ever touch on so far.
3) Financial hegemony: As the world's premier capitalist power, and center of world finance, the USA possess unrivaled clout not just in how much money their banks and corporations can throw at problems, they also control financial infrastructure. I think I don't need to explain how the American government, through the threat of punishment against American and foreign companies, can greatly complicate, to the point of making it prohibitively difficult, trade deals and financial transactions between their allies (who are using the US controlled financial infrastructure) and third nations. The Europeans wanted to keep trade open with Iran after Trump put the sanctions in place, but that went nowhere because the EU did not manage to set up financial infrastructure despite very much wanting to do so. This was mostly about payment clearance, insurance, and such. As a result, no European company dared trade with Iran, and the independent EU foreign policy vis a vis Iran, just didn't happen. The EU nations protested, but had to follow the US decreed rules about not trading with Iran.
Instead i would argue that the EU is hegemon over Europe as it has effectively morphed into a political entity unto itself post Maastricht, even after Brexit.
The EU is indeed a political entity in itself, polycentric but distinct. And it's a big player in Europe. The EU basically does what it wants vs the non EU Balkan nations in economic and security matters, it's strong enough for hat.
In matters of security beyond the Balkans, though, such as the issues vs Russia, military problems on the direct periphery (Libya), the EU is not capable of action without US green light and support. That's how weak the EU is, and why the USA are the regional hegemon.
Worth noting only the UK joined the US in the Iraq war and there was minimal European involvement in Vietnam, the Gulf and Afghanistan.
Hegemony isn't when everyone follows you on every step, it's when there's one and only one power that is indispensable for everyone else
