Joshua Blessinger who served in the Marines from 1999 to 2003 he said he was surprised it didn't happen earlier.
"Even back in 2003 when we were first going in we knew it was going to happen whenever you have a vacuum of power," said Blessinger. "Those insurgents will try to gain power, and you will have the strong pushing the weak."
Blessinger was apart of the first wave going into Iraq in 2003. He believes this issue is more complicated than people realize, and it is a centuries old conflict between Sunni and Shiite Muslims.
Blessinger said he thought the U.S. shouldn't have left in the first place, but said now that we're gone he doesn't want to see troops go back in.
While President Obama hopes the 300 advisers will help the Iraqi Army get the upper hand, veterans like Blessinger say the army there is the biggest problem. Reports surfaced that Iraqi soldiers fled in large numbers, leaving behind uniforms and weapons.
"We've had since 2003 to get them ready to fight, and they just got creamed," Blessinger said.