As presidential hopefuls in the crowded Republican field strive to break out of the pack, the question of sending U.S. troops back to the Middle East, this time to tackle Islamic State of Iraq and Syria (ISIS/ISIL) jihadists, is gaining prominence.

Leading the running on the issue is Sen. Lindsey Graham (R-S.C.), who has gone beyond anyone else in the race by calling for tens of thousands of American troops to be deployed to Iraq – and to Syria.