The Iran deal and multipolarity

I'm not the first to comment on the US' decision to leave the Joint Comprehensive Plan of Action (JCPOA) nor will I be the last. Most seem to comment on what the deal was and why it should or shouldn't have been abandoned or what this means for the politics in the Middle East. And while those are very interesting questions others have written extensively on the topic much better than I could so I will instead turn to something I find significant which most don't seem to care about. On of the most interesting things about the US' withdrawal is that their European partners still want to stay in the deal. To me this is a sign of how the interests of Europe and America seem to have started to diverge lately. Paralell to the Iran deal there are talks between the EU and the USA about US President Donald Trump's proposed tariffs on aluminium and steel. Here too did the US unilaterally make a desicion which upset Europe, seemingly without talking to European countries first. I sense that these are the some of the first small signs of multipolarity, a world with three or more great powers. Maybe Europe no longer wants to be the US' lapdog.