The NATO meeting in Chicago this weekend is a chance for alliance leaders to proclaim solidarity and promise success.
But the gathering probably won't resolve the underlying anxiety about sharing the burdens of defense. That's a concern heightened by Europe's economic crisis and America's growing weariness about carrying the heaviest load.
Drastic budget cuts in some European countries are exasperating tensions over a big gap in military capabilities between the United States and other NATO members.
From NATO's birth in 1949 at the dawn of the Cold War, the U.S. has provided the bulk of the military might. That arrangement, however, is fraying in an age of austerity and in the absence of a Soviet-like invasion threat to compel more military spending by the Europeans.