Several readers have asked why I don't think the accession countries will tip the balance of power in the EU towards the United States. The declarations from the Gang of Eight and the Vilnius 10 were hugely significant, but they signal the start of a struggle for the soul of European institutions, not the end of one. The outcome is far from a foregone conclusion, and prematurely assuming a battle is won is the easiest way to lose it.
That more than 15 heads of state would come out in support of the United States despite overwhelming popular opposition at home is a spectacular but singular event. It would be folly to build foreign policy around the notion that the UK and "new Europe" will remain united and in synch with US policy forever. This sort of unity happens only around big issues like the Iraq war -- in everyday life, countries will pursue their own interests and will "go along to get along."
Which means that a real danger arises from the tendency of the EU towards largely unaccountable institutions that restrict the freedom of member countries to act independently. When the old European political elite promote a "common" foreign policy, they aren't talking about a show of hands amongst the leaders of member nations. They envision a European Foreign Service, populated by bureaucrats and led by an appointed commissioner who is selected from the ranks of the politically acceptable. In their EU, such an institution would be accountable to nobody and have the legal authority to muzzle dissent. In their EU, the Gang of Eight could have faced legal action for their declaration.
The smaller countries understand the danger and are now making an effort to retain autonomy and gain some measure of control over the Eurocracy (thanks at least in part to both Donald Rumsfeld and Jacques Chirac). This is an important development and one whose success is important to the United States, which is why it would be a huge mistake to undermine friendly leaders with a blatant assault on the UN or heavy-handed attempt to "punish" France, Russia or Germany.
Chirac and his minions have been jockeying for position in Europe for some time now, and their policy toward Iraq is designed to undermine European leaders who don't toe the French line. Popular discontent makes it much harder for European leaders to appear to side with the United States, so look for Chirac et al to exploit European devotion to the UN and fear of the American bogeyman to stoke the fires of anti-American passion already enflamed by the war itself.
In particular, they will keep trying to frame discussion about the future of Iraq as a "United States vs. the United Nations" issue. Bush and Blair struck the right tone in their Northern Ireland press conference by setting Iraqi self-determination as the centerpiece, but the weasel-bloc will use their upcoming St. Petersburg conference to once again attempt to force the issue.
Update: They won't be quite this bold, especially since Annan has decided not to attend, but don't think for a second that they've stopped scheming.