Secretary of State John Kerry, left, speaks with Treasury Secretary Jacob Lew, as they testify on Capitol Hill in Washington, July 28, 2015.

Secretary of State John Kerry, left, speaks with Treasury Secretary Jacob Lew, as they testify on Capitol Hill in Washington, July 28, 2015. J. Scott Applewhite/AP

September Will Be Make or Break Month for the Iran Deal in Congress

The August recess will give leaders and outside groups ample time to drum up support for their sides.

Congress will vote in September on a resolution of disapproval of a multinational deal with Iran aimed at preventing it from acquiring a nuclear bomb, Republican leaders announced Tuesday

Both Speaker John Boehner and Senate Majority Leader Mitch McConnell said their chambers would take up Iran measures after the August recess.

Given the significance of the issue, McConnell said he plans to set up an unusual debate to discuss the Iran deal, canceling committee hearings so that the entire Senate can sit together (perhaps for hours on end) and debate the issue, rather than allowing members to speak on the issue to C-SPAN cameras alone.

"I'll be trying to get the Senate to have a debate in which we have time set up for each senator to speak, and we'll be asking for each senator to remain at their desk during the debate and actually listen to each other during the course of the debate, leading to a final vote," McConnell announced Tuesday. "So I think this issue is of such magnitude that I hope we will not be having committee meetings [and] we'll actually have a debate that rises to the occasion that this seems to require."

House Majority Leader Kevin McCarthy said in a statement that the House will vote on a resolution introduced Tuesday by Foreign Affairs Committee Chairman Ed Royce. But he also noted that the resolution is only part of the issue, pointing to a letter from nearly 100 House members to the president asking that as-yet unrevealed parts of the deal struck between Iran and the International Atomic Energy Agency be made public.

(See also: 9 Reasons the Iran Deal Makes Sense)

"Everything we have learned about this agreement has given Congress and the American people cause for grave concern. Iran still has a legitimate path to a nuclear bomb, Iranian leaders and the Obama Administration have expressed major public disagreements on key tenets of the deal, and 'snapback' sanctions are a fallacy," McCarthy said. "What's worse, at least two side deals have been made between Iran and the [IAEA] and, thus far, the Obama Administration has refused to share the text of the side deals with Congress. It is clear that this is a bad deal, and the House will vote on disapproval in September."

The administration, however, has disputed that the deals are secretive, instead referring to them as standard technical arrangements, the contents of which will be shared with Congress in a classified briefing.

The Obama administration has already pledged to veto any resolution of disapproval, so only a two-thirds majority would send a strong message that Congress can sustain the measure even if Obama vetoes it. That will be hard to achieve in the House, where only a handful of Democrats have declared their opposition, and House Minority Leader Nancy Pelosi has said several Democrats have pledged to her they would help sustain a veto. The Senate remains an open question, but so far there has not been a tide of Democrats against the deal in that chamber either.

The August recess will give leaders and outside groups ample time to drum up support for their side. Boehner, who has long expressed skepticism of the deal, said in a statement that members can take the August recess to become familiar with its text.