With the Obama Administration’s announcement of the long-postponed international nuclear agreement with Iran, it is now time for the U.S. Congress to weigh in. According to the Iran Nuclear Agreement Review Act, passed and signed into law earlier this year, Congress will have 60 days to review the deal—or choose not to act.

The Joint Comprehensive Plan of Action (JCPOA), reached after intense diplomatic negotiations in Vienna, would provide Iran with relief from economic sanctions in exchange for limitations on its nuclear program. In the United States, there has been broad bipartisan agreement on three fundamental principles with regard to Iran: that the goal should be preventing Iran from obtaining a nuclear weapon; that diplomacy is a preferable course of action compared to other alternatives, especially military options; and that economic sanctions are an effective tool of foreign policy. The disagreement comes over whether or not this particular deal will successfully prevent Iran from acquiring a bomb and meet American national security interests.

Over the past several months, members of Congress from both parties have expressed significant skepticism about the nuclear deal, particularly when it comes to inspections, verification, and enforcement. In the coming months, Congress has the opportunity to debate, hold hearings, and even vote on a resolution to approve or reject the deal.

Congress is likely to wait until after the August recess to vote on a resolution, according to Senate Foreign Relations Committee Chairman Bob Corker. Even if Congress does pass a joint resolution of disapproval in the fall, however, that would not necessarily kill the deal. President Obama could veto the resolution, which would take a two-thirds majority in both the House and Senate to override. Reaching a veto-proof majority would take every Republican in Congress in addition to 44 Democrats in the House and 13 Democrats in the Senate.

Senate Majority Leader Mitch McConnell recently said the president “knows that the resolution of disapproval is likely to be introduced, is very likely to pass and very likely to get over 60 votes.” That indicates Senate leaders believe there will be a bipartisan majority to reject the deal but not enough votes to override a presidential veto.

President Obama has been clear about his intention to veto a resolution of disapproval from Congress. In his statement at the White House, while saying he supports the opportunity for Congress and the American people to review and debate the deal, the president also asserted, “I will veto any legislation that prevents the successful implementation of this deal.”

The political realities of the president pursuing the Iran deal by vetoing a bipartisan resolution of disapproval from Congress are problematic. In doing so, President Obama would effectively be unilaterally lifting U.S. economic sanctions against Iran that were originally passed by Congress—explicitly against the reiterated will of Congress to keep those sanctions in place.

In fact, the administration has opposed a congressional role in the Iranian nuclear negotiations from the beginning. Although the Iran Nuclear Agreement Review Act passed the Senate by a vote of 98-1 (the single vote against it being Senator Tom Cotton, who wanted the president to submit the deal as a treaty—thus constitutionally requiring a two-thirds majority vote to pass) the Obama administration will now bypass Congress entirely by going to the United Nations Security Council to seek a resolution endorsing and implementing the deal by lifting sanctions before the congressional review period is over.

One provision of the JCPOA agreement worth noting in particular is Section 37, which states, “Iran has stated that if sanctions are reinstated in whole or in part, Iran will treat that as grounds to cease performing its commitments under this JCPOA in whole or in part.” That could mean that if the United States or the United Nations re-impose sanctions, even in response to potential Iranian breaches of the agreement, Iran would no longer be obligated to keep its JCPOA commitments with regard to limiting its nuclear program.

Skepticism from congressional leaders cuts at the very premise of the Iran deal. As Democratic Senator Robert Menendez recently said, “We have gone from preventing Iran having a nuclear ability, to managing it.” Whether or not Congress will even be allowed to play a role at all, however, remains to be seen.