I tend to reject plot theories, in 99% of the cases they are total bullshit!!
There are three common beliefs among elites in Europe:
1) The US never wanted a strong EU and UK, thanks to its special relationship, was in charge of this task;
2) The US has any interest to keep the tension with Russia high to avoid a re-approachment between EU and Russia;
3) Nato did not had to encompass Eastern Europe, EU did, but rules did not go thru since Europeans rejected the EU constitution thru a referendum and we got stuck and with an enlarged EU with old rules that could never work;
My reaction is that number one is not at all the case. The U.S. was an early promoter of the EU. The U.S. teamed with the EU to organize and carry through most of the early GATT rounds of trade liberalization. The so called Special Relationship suffered badly after the Suez caper. Brits were always divided about the EU. Even British proponents of joining the EU never really embraced the idea of an ever closer union. I think the British efforts over the years to impede the EU were entirely home grown and not the result of any American instigation. I think DeGaulle was right to keep them out in the first place. The Brits have never considered themselves European. They never wanted to part of a closer union. Indeed, the didn’t want to be part of any union they couldn’t control.
On number 2, I don’t think the U.S. specifically wants to stop a Russian-EU rapprochement. Rather a powerful element in the U.S. loved the Cold War and has wanted to keep it going not for purposes of starting or stopping anything in Europe, but for purposes of keeping the U.S. National Security/Foreign policy establishment in business and in power. This is the primary aim. Now it may be that this aim entails undermining EU-Russian efforts at rapprochement.
Yes, there was no need to extend NATO to eastern Europe. It was a big mistake in my view. But it was done on the basis that the Russians could not be trusted in the long run and that we should do the extension as fast as possible while Russian was weak so that it would be a Fait Accompli. Yes, the EU could have been broadened without an extension of NATO. Rejection of the EU constitution while broadening under the old rules was a bad move. Europe is suffering for that now.