Senators: Iran fight could make ISIS debate more difficult

Senators on Tuesday said acrimony between Republicans and Democrats over Iran made reaching an authorization for military force against the Islamic State in Iraq and Syria (ISIS) a little more difficult. 

Forty-seven Senate Republicans sent an open letter to directly to Iran this week, warning that any deal negotiated to rollback its nuclear program might not last beyond President Obama, outraging Democrats and the White House. 

However, reaching an authorization for the use of military force (AUMF) will take bipartisanship, and both sides already disagree on how it should be worded, noted Sen. Jeff FlakeJeffrey (Jeff) Lane FlakeTrump's attacks on McCain exacerbate tensions with Senate GOP Schumer to introduce bill naming Senate office building after McCain amid Trump uproar Trump keeps tight grip on GOP MORE (R-Ariz.). 

"It's a difficult environment. There's a lot of animosity, obviously, and that has manifested in a lot of these issues, but these are too important to let divide us," he added.

But he added, "I think we can get there, I hope we do. Our allies and our enemies need to know that we speak with one voice."

Sen. Bill NelsonClarence (Bill) William NelsonEx-House Intel chair: Intel panel is wrong forum to investigate Trump's finances The Hill's Morning Report - Trump budget reignites border security fight 2020 party politics in Puerto Rico MORE (D-Fla.) was less sanguine.

"When 47 Republican senators try to cut the legs out from under the president and negotiations that are proceeding now in Geneva -- I was flabbergasted and if that can happen in these days, then I can't predict anything with the AUMF," he said.

Nelson said he was "absolutely appalled and saddened by" partisanship being injected into foreign policy and national security.

"What it sends is a message  to the rest of the world is that we are not united when these kinds of letters are being written," he said. 

The Senate Foreign Relations Committee is scheduled to question Secretary of Defense Ash Carter, Secretary of State John KerryJohn Forbes KerryBiden leads CNN poll, but Harris, Sanders on the rise Beto is the poor man's Obama — Dems can do better Joe Biden could be a great president, but can he win? MORE, and Chairman of the Joint Chiefs of Staff Gen. Martin Dempsey on Wednesday morning as part of its efforts to craft an AUMF. 

Sen. Susan CollinsSusan Margaret CollinsSenate GOP poised to go 'nuclear' on Trump picks Overnight Health Care: CDC pushes for expanding HIV testing, treatment | Dem group launches ads attacking Trump on Medicare, Medicaid cuts | Hospitals, insurers spar over surprise bills | O'Rourke under pressure from left on Medicare for all Dem group launches ads attacking Trump's 'hypocrisy on Medicare and Medicaid cuts' MORE (R-Maine) said it's difficult to predict whether there would be an AUMF reached. 

"It has not resonated very well with people on either side of the aisle for totally different reasons so I'm not sure what the outcomes could be," she said.