NATO, Europe and the US.

Military.com has an article detailing the movement of a US Army Combat Brigade out of Europe.  I find it surprising that moving so small a formation could cause so much controversy.  Read the article but this stood out.

First this...

Moving the brigade would weaken the NATO alliance, said Ståle Ulriksen, chair of the Security and Conflict Management Department at the Norwegian Institute of International Affairs in Oslo. Norway, for instance, went to Afghanistan, like the other European nations, "to show solidarity and to stay on the good side of the U.S. -- to be an ally," he said.
Ulriksen said that "free-riding" on the U.S. had enabled Europeans to avoid devising their own coordinated defense structures and that they should "grow up and take responsibility."
But he also said a European alliance was hard to imagine without the U.S. as leader.
"It's a kind of a comfortable situation. You have a leader no one disputes," he said. "What would be the alternative -- the British? The French? The Germans?"

and then this...

In the House, Rep. Barney Frank, D-Mass., spearheaded a plan last year to eliminate an Air Force fighter wing overseas, two Marine Corps infantry battalions on Okinawa -- and one Army brigade in Europe.
"NATO was a wonderful concept. But 61 years later, I think it's time to say our Western European allies should be on their own. We'll cooperate with them, but we shouldn't be subsidizing their defense," Frank said.

In the Senate, Sen. Kay Bailey Hutchison, R-Texas, whose state stands to gain troops at Fort Bliss in the restructuring, was advocating similarly.
"For the future security posture of U.S. military forces and for the fiscal health of our nation, [the] military construction agenda should be guided by these words: build in America," she wrote in Politico last year. "Some argue that the U.S. overseas presence provides assurance to our allies and deterrence to our adversaries. History has proven otherwise."

Long story short.

US forces will be coming home.  Europe will have to stand on its own two feet.  The alliance, if its to survive, must evolve.

Notice one thing.

You have a prominent Republican and Democrat saying the same thing.  They're reading the political winds.  Forward deployed forces on even allied soil is something that the American people are tiring of.