Exposing a few dozen Marines to a potentially catastrophic attack by Islamic terrorists is not going all-out to defeat the barbaric murders. It is taking a terrible risk with American lives, however.

After the terrorist bombings in Belgium, President Barack Obama pledged to do all in his power to destroy groups such as the Islamic State.

He has not come even close to that during his seven years in the White House.

Instead, with obvious reluctance, he has authorized use of handfuls of U.S. troops to fight the IS in Iraq and Syria.

Recently, a small Marine artillery group was sent to an outpost in northern Iraq to provide support for Iraqi troops battling an IS force. Pentagon officials will not say how many Marines were deployed, but the number is less than 200.

U.S. officials refuse to admit the Marines are even combat troops. The explanation for that is the Marines are not on the front lines with Iraqi infantrymen. They are several hundred meters back from the front.

But the Marines are firing four 155mm howitzers at terrorist forces – and IS already has targeted the Americans. Recently, a rocket hit the U.S. position, killing one Marine and wounding several others.

Beyond any reasonable doubt, IS leaders would love to find a way to massacre every Marine in the unit – and those in the few other small groups of U.S. troops in Iraq.

Instead of exposing U.S. troops in small, vulnerable units, Obama should be using larger forces. Not doing so may be politically correct – but it is putting Americans at risk unnecessarily.