America out of Europe
There's also the matter of Washington's reported plans to start moving troops and weapons systems from Europe to the Indo-Pacific region. The foreign ministers of NATO's four Asia-Pacific partners — Australia, Japan, New Zealand and South Korea — will attend this week's meeting.
There are even reports that Washington may seek to hand over the role of Supreme Allied Commander Europe, the alliance's top military job, to a European — for the first time since NATO's founding.
Another irritant is efforts by the EU to boost its domestic defense industry with the use of special funds — projects that will likely largely exclude U.S. arms-makers, which is angering Washington.
The main conversation about "burden-shifting" is expected to take place later among defense ministers, then in June when NATO leaders gather in The Hague. But European capitals are still pushing for clarity on the pace of plans to move assets out of Europe.
One of the most pressing issues for Europeans is how to replace so-called enablers, such as surveillance, reconnaissance and targeting abilities, as well as command and control systems and air refueling aircraft, which are currently mainly provided by the U.S.
German Defense Minister Boris Pistorius is hoping to define a roadmap with the U.S. to anticipate any withdrawal or decrease of American assets and troops in Europe, he told reporters in Paris last month, but hasn't heard back from Washington yet.
Any move on shifting burdens "needs to be consulted" within NATO, said a senior EU diplomat. "It needs to happen in such a way that if the Americans reduce their presence in Europe — in any way, shape or form — that that happens with a pace that we can fill the void.”