A senior military official tells NBC News that five years of combat in Iraq and Afghanistan have stretched the Army to a dangerous breaking point.
For the Army, the pace of combat has been relentless. Many soldiers are already on their third combat tour. Frequent deployments have cut training time at home in half, which has left two-thirds of all Army combat units rated "not ready for combat."
"I think, arguably, it's the worst readiness condition the U.S. Army has faced since the end of Vietnam," says NBC military analyst and retired Gen. Barry McCaffrey.
So the Army's looking again to the National Guard for relief.
A year ago, more than one-third of U.S. ground forces in Iraq were National Guard. Guard chief Lt. Gen. Steven Blum is prepared for his soldiers to get the call again.
"If you think the National Guard is busy today, I think we're going to look back and say these were the good old days in about three years," Blum says.
But the Guard is also under stress. Two hundred seventy thousand Guard soldiers — 60 percent of the force — have already hit their limit for overseas combat. The Pentagon would have to change its policy that limits Guard combat tours to two years out of five.
"More is being asked of them, particularly the National Guard and Reserve components, than they signed up to do," says McCaffrey, "and in the near term we think it's going to unravel."
Perhaps worse, most Guard equipment, like Humvees and trucks, has either been destroyed or left behind in Iraq. That makes it difficult for the Guard to train — or to fulfill its primary duty: respond to disasters here at home.
"If you want the Guard to do a mission three years from now, no one should be surprised that they're ill-equipped, or under-equipped to do the job," says Blum.
Blum remains confident, however, that if needed the Guard will answer the call.
But uprooting Guard soldiers from their families and sending them off to war is politically explosive, so military officials predict there will be no decision to mobilize the Guard until after the midterm elections in November.