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(CNN) – Asked whether U.S. inaction in Syria paved the way for the Iraq crisis, the top Democrat on the House intelligence committee admits the U.S. could have done more.
"Looking back, maybe we could have been aggressive, but that's looking back, and let's learn from that," said Rep. Dutch Ruppersberger, D-Maryland.
"ISIS is just a small part of what's happening in Syria," he said, referring to the Islamic State in Iraq and Syria, the militant group that has taken vast swaths of northern Iraq from government hands.
Critics charge that the Iraq crisis is blow back for the U.S. not taking initiative in Syria, and not supporting the moderates, thus allowing ISIS to thrive.
On Wednesday, the chairman of the Joint Chiefs of Staff told Congress that the United States has received a request from the Iraqi government to use its air power to help drive back militants battling for control of the country.
As the U.S. weighs military options in Iraq, Ruppersberger says there needs to be a coalition, adding that the U.S. "can't be the sheriff of the whole world."
But the Maryland Democrat is wary of the U.S. cooperating with Iran on the Iraq crisis.
"I think Iran exports terrorism. I wouldn't trust Iran at this point," Ruppersberger said.
Iran's government has a close relationship with Iraq's Prime Minister Nouri al-Maliki, and if they can "influence Maliki to bring the Sunni and the Kurds back in the tent to really deescalate what is happening, we should at least use them from that point of view," he said.
"But I would have a very difficult time trusting, or working with Iran," said Ruppersberger.
For more of our interview with Rep. Dutch Ruppersberger, check out the video above.