While the U.S. military rushes to switch on its ballistic missile defense system, the Pentagon's program for combating cruise missiles is in deep trouble, Aviation Week reports. And it may not get better for a long, long time to come.

China, Iran, and Syria are among the countries building up big arsenals of land-based cruise missiles, which are seen by some analysts as a bigger threat to American security than any ballistic danger. That's mostly because the missiles are so easy to obtain. "For the price of two fighters or four attack helicopters a country can buy about 40 cruise missiles," Aviation Week notes.

The Patriot missile defense system is supposed to provide some protection against the threat. But the Patriot's track record is iffy. And Patriots are expensive -- $2 to $3 million per shot.

So the Defense Department wants a smaller, more mobile, more accurate, cheaper solution. And it wants the system by the end of the decade.

But it ain't gonna happen, Aviation Week says. The Patriot's replacement, the Medium Extended Air Defense System, now isn't scheduled to come online until 2015.

It's one of a whole lot of hurdles the Pentagon is going to face as it tries to stop cruise missile attacks, says Victoria Samson, with the Center for Defense Information.

"I think what we are going to find out is that ballistic missile defense is a cakewalk compared to cruise missile defense," she tells Defense Tech. Tracking ballisitic missiles is hard. But "when you factor in something that is powered, can fly low to the ground, and has a much lower radar cross section, the job gets much more difficult. As we saw in [the Iraq war], when Iraq cobbled together old Seersucker cruise missiles and used them over land (instead of over the water, as they were designed) against Coalition troops, not only did we not engage them with the Patriot, but we flat-out failed to pick them up on our radar."