Feeding more American troops into Iraq little by little is an invitation to disaster, yet President Barack Obama persists in the practice.

Obama vowed U.S. military involvement in Iraq was over in December 2011. But Islamic terrorists have conquered much of the country since then.

In June 2014, he sent 170 Army advisers to Iraq. Since then, that force has been augmented in small groups. This week, another 217 advisers were deployed, bringing the total to about 4,000.

Small U.S. military units are vulnerable to attacks, some of which have been made by the terrorists. More may follow.

Unless Obama recognizes there is weakness in lack of numbers, the enemy will have an opportunity to exploit it – perhaps with bloody, tragic results.