One of the Senate’s leading hawks, Sen. Lindsey Graham (R-SC) on Sunday urged President Obama work with Iran about coordinating their response to sweeping gains by the insurgent Islamic State of Iraq and Syria.

“The Iranians can provide some assets to make sure Baghdad doesn’t fall,” Graham said on CNN’s State of the Union. “We need to coordinate with the Iranians and the Turks need to get in the game and get the Sunni Arabs back into the game, form a new government without [Iraqi prime minister Nouri Al-Maliki.]”

Close video ISIS offensive poses threat to Middle East stability TJ Holmes talks to MSNBC Military Analyst Col. Jack Jacobs and NBC’s Ayman Mohyeldin about the effect ISIS will have on the Middle East and the U.S. home front. share tweet email Embed

Iran, like Iraq, is a majority Shiite country and has an interest in preserving the government, which has been dominated by Shiite leaders since the U.S. toppled Saddam Hussein’s secular Baathist regime and installed a new elected government. Iranian officials have pledged to help Iraq’s government in its fight and some reports indicate they’ve already sent soldiers to aid in the battle.

ISIS, which seeks to install a Sunni Islamic state in the region, stunned the world last week with a rapid invasion that dislodged government forces from Mosul and Tikrit, two major Iraqi cities, among other areas. Formerly affiliated with al-Qaeda, ISIS broke with the terrorist group in part because al-Qaeda leaders considered their violent tactics too extreme. Those tactics were in full display after their invasion as ISIS released gruesome videos of firing squads murdering unarmed prisoners. The video is unverified, but the group claimed they executed 1,700 Shiite Iraqi soldiers.

Graham warned on Sunday that unless America takes the lead in providing air power and military advisers to defeat ISIS, the government will collapse and Iran will move into Iraq’s Shiite South, strengthening its own hold on the region.

“We should have discussions with Iran to make sure they don’t use this as an opportunity to seize control of parts of Iraq,” Graham said on CNN’s State of the Union. “They’re in this. They’re already on the ground. We need to put a red line with Iran.”

Host Dana Bash was shocked by Graham’s suggestion of direct talks and even cooperation with Iran given his longtime hardline stance against the Islamic state.

“I’m sorry, it’s sort of hard for me to believe that I’m hearing a Republican say, ‘Sit down and talk with Iran,’” she said.

Close video Mitt Romney weighs in on Iraq Melissa Harris-Perry’s panelists continue their discussion about the ongoing crisis in Iraq and the potential responses from the U.S. government. share tweet email Embed

Mitt Romney, appearing on NBC’s Meet The Press , said “much of the blame, the great majority of the blame, has to be laid at the feet of the Iraqi leadership” for the insurgent gains. But he attacked President Obama for not taking a harder stance in withdrawal negotiations with Iraq to leave a residual force of American troops and for not taking a more active role in the Syrian civil war.

“This administration, from Secretary Clinton to President Obama, has repeatedly underestimated the threats that are faced by America,” Romney said.

Politicians, Iraq experts, and former military officials appearing on Sunday shows were divided over the proper response to the ISIS threat. Some favored air strikes and even inserting limited ground forces to direct them. Others suggested it risked plunging the American military into a sectarian war that could only be resolved politically.

One area where there was strong consensus, however, was the disastrous role Maliki’s government played in precipitating the ISIS invasion by alienating the country’s Sunni and Kurdish population.

“He should resign,” Graham said on CNN. ”He’s incapable of bringing the Sunnis back into the fold.”

“What we’re seeing essentially is a consequence of his extremely sectarian policy,” New Yorker reporter Dexter Filkins, a longtime combat correspondent, said on NBC’s Meet The Press.

Retired Army General Peter Chiarelli, who oversaw operations in Iraq, said on ABC’sThis Week With George Stephanopolous that the primary reason the Iraqi military deserted in large numbers was that Sunni soldiers saw little stake in battling a Sunni religious movement in order to prop up a government that had persecuted them.

“There’s no doubt they have the equipment, there’s no doubt they have the training, the problem is they have no trust in their government,” he said.