A breakdown in high-stakes budget talks in Congress could threaten plans for a missile defense shield in Europe.
Negotiators have shown little sign they will be able to meet next week's deadline for reducing the deficit by $1.2 trillion. If they fail to agree, a new law mandates cuts throughout the federal government, including a big slice of the defense budget.
While it is not known what military spending would be cut, an expensive program aimed primarily at defending Europe is unlikely to be spared.
The U.S. sees the missile defense system, aimed at countering a threat from Iran, as part of its contribution to the NATO military alliance. With the United States often complaining that it makes a disproportionately large contribution to NATO, missile defense could be especially vulnerable to budget-cutters.
"A missile defense system for NATO? It's going to be hard to keep people committed if they think the U.S. is picking up the tab for Europe," says Kurt Volker, who was ambassador to NATO at the end of the George W. Bush administration.
Defense Secretary Leon Panetta has warned that the European missile defense program could be threatened if the special negotiating panel, known as the supercommittee, should fail to work out a deal. That suggestion, though, may have been intended mostly to nudge lawmakers to resolve their differences and avoid the automatic cuts to one of their favorite programs.
It is still possible that supercommittee members could set aside intense partisan differences and reach a deal by Wednesday. And if they do not, Congress might find a way to cancel the cuts before they take effect in 2013.
That may only delay the scaling back of the U.S. military role in Europe. A decade-long expansion of military spending appears to be coming to an end, and the Obama administration has indicated it is shifting its foreign policy toward Asia, where it sees the greatest opportunities and threats of coming decades.
"Where does that leave Europe? Lower down the list," says Todd Harrison, senior fellow at the Center for Strategic and Budgetary Assessments.
Beyond missile defense, the automatic cuts could prompt the U.S. to save money by shifting some warships away from Europe but probably would not lead to fewer U.S. troops there.
The United States has already reduced its presence in Europe from more than 200,000 in 1989 to slightly more than 40,000 today. It has plans for a further pullback by 2015 but is unlikely to accelerate that simply because there are no short-term savings to be had from moving troops out of their European bases.
"We can't take the remaining bases with us," says Christopher Wiley, an analyst with the Transatlantic relations program at the Bertelsmann Foundation who is preparing a report on the impact of budget cuts on U.S. policy in Europe. "It's not a good place to save cash."