The effort to sway the president’s party against the deal hit a setback on Tuesday, when the Washington Post reported that Senators Tim Kaine, Barbara Boxer, and Bill Nelson all came out in support of the deal. But a handful of Democrats have expressed explicit opposition, and many others are on the fence. These will face tough lobbying efforts and pressure from congressional opponents of the deal over roughly the next six weeks.

The National Journal also reports that Senate Majority Leader Mitch McConnell plans to take the uncommon step of assembling the entirety of the Senate to debate the issue, potentially for several hours. In addition, an upcoming August recess will give political organizations ample time to communicate with undecided congressmen in person.

Speaker of the House John Boehner told reporters that the recess would also give congressmen an opportunity to familiarize themselves with the lengthy text of the agreement. This may be of particular significance to those who intend to vote their conscience but are uncertain of some of the specific content of the deal. Among them is Democratic New York Senator Charles Schumer, who remains on the fence but has emphasized his prior willingness to break with the president over matters of importance to him, including those that affect the security of the state of Israel.

The August recess may resolve some uncertainties about the agreement, but it seems that others may remain. Nearly 100 members of the House recently signed a letter urging the White House to release the text of so-called “side deals” between Iran and the International Atomic Energy Agency, which may provide a clearer picture about how the process of verification would work and to what extent Iran will be expected to come clean on the past military dimensions of its nuclear program.

But The Blaze reported on Tuesday that the White House responded to concerns about these side deals by saying that it has not even seen the text of the Iran-IAEA agreements. While the Obama administration has evidently been briefed on the general contents of those documents, it has not yet conveyed this briefing to Congress. Even if it does so, the lack of access to the documents themselves remains as a significant source of skepticism for persons who remain uncertain about the nuclear agreement and its corollaries.

If this issue remains outstanding throughout the August recess, it will be another source of pressure on undecided Democrats, alongside lobbying from Republicans, constituents, and opponents of the Iranian regime including a number of pro-Israel groups.

However, even some Jewish groups remain on the fence. Fox News reported on Tuesday that President Obama would be meeting with several Jewish groups that day to discuss the nuclear deal, fielding criticisms from some while attempting to elicit support from others.

But in a webcast organized by groups opposed to the deal, Israeli Prime Minister Benjamin Netanyahu addressed 10,000 participants by reiterating his claim that the nuclear agreement does not block Iran’s pathway to a nuclear deal, but rather paves it. He also rejected the Obama administration narrative claiming that the only alternative to the existing deal is war. Many opponents of the agreement believe that the weak status of the Iranian regime, a consequence of both economic sanctions and domestic unrest, makes it possible to press the regime to make much greater concessions.