Islamic State terrorists poised to conquer Iraq will suffer from U.S. airstrikes – but that will not be enough to defeat them. Only attacks on the ground can do that.

After President Barack Obama approved airstrikes against Islamic State forces late last week, some observers breathed sighs of relief. Even a few in the military predicted U.S. air power will be decisive.

It will not. Americans have learned that in multiple conflicts since World War II.

Fortunately, some in the White House seem to understand. This week Obama revealed he also is sending weapons to Kurdish forces in northern Iraq.

Americans have no stomach for a return to Iraq by the large number of U.S. troops that would be necessary to defeat Islamic State forces. Even use of airstrikes, if they are mounted by piloted warplanes, is risky.

Allowing the Islamic State to take over Iraq is unacceptable, of course. To avoid that, U.S. officials should provide Iraqis, including the Kurds, with help sufficient to mount the ground attacks that can win the war.