NATO wants member nations to share common defense

Two F-4 jet fighters streaked off a runway in Lithuania this week to intercept a mystery plane in an exercise NATO officials hope showed the benefits of different countries shouldering different parts of a common defense program.

NATO has provided air policing for the Baltic countries -- Lithuania, Latvia and Estonia -- since 2004 because they can't afford it themselves. In turn, those countries have sent troops to Afghanistan.

With national budgets shrinking, NATO officials hope member countries at a May summit in Chicago will decide to share, and forgo, resources in a coordinated way.

National governments are often reluctant to cede sovereignty over defense. But a NATO offical in Brussels said this week that because of austerity "the ground has changed."