Washington, DC – In what is surely the first of what will be several competing attempts to try and block the nuclear deal negotiated with Iran, 166 House Republicans have introduced a resolution to block the Joint Comprehensive Plan of Action (JCPOA), even before President Obama has formally submitted the agreement for Congressional review.

H.Res.367, introduced by Illinois Representative Peter Roskam (R-IL-6th) and all but eighty of his Republican colleagues in the House, “expresses its firm disapproval of the Joint Comprehensive Plan of Action” and lists a litany of criticisms–many of which were directly addressed by President Obama during his press conference on Wednesday. Were the resolution to pass, the President would be blocked from issuing sanctions waivers to implement the agreement.

Under the Iran Nuclear Agreement Review Act (INARA), which was passed into law in May, Congress has 60 days to review the deal and decide on a course of action. So long as congress doesn’t pass a disapproval resolution, the deal can move forward.

If both chambers of Congress do pass a disapproval resolution, it would prohibit the President from waiving any Congressionally-mandated sanctions against Iran. The President can veto the resolution, in which case both chambers would need to garner a two-thirds majority to override it and block the deal. If they succeed, the President would be limited to easing sanctions that have been imposed only by Executive Order–which would not be sufficient for the U.S. to meet its obligations under the agreement and effectively kill the deal.

Under INARA, Congress can also vote to approve the deal. The passage of such a measure is not necessary for the deal to go forward. However, Senate Majority Leader Mitch McConnell (R-KY), has indicated that he may stage a vote on approval measure as well as a disapproval vote in an attempt to demonstrate “unmistakable signal about congressional opposition to lifting sanctions.”

Such a move appears to be designed to put pressure on Democrats –who are more inclined to support the President’s signature foreign policy achievement- by putting them in the crosshairs of powerful lobby groups such as AIPAC who are opposed to the deal. It may be that the opponents of the deal are hoping this will be enough to get enough Senate Democrats to switch sides to override President Obama’s veto. Opponents of the deal may also be positioning themselves for follow up action in case they cannot block the deal through the INARA process. Opponents may argue that weak support for an approval vote, and a Presidential veto to block disapproval, offers them a mandate to weaken or dismantle the agreement through further legislative action.

Over the next several weeks, the Senate Foreign Relations Committee will hold hearings to evaluate the Iran agreement. The administration is expected to give a full-throated defense of what most non-proliferation experts have dubbed as a good deal. The first announced hearing will feature three members of President Obama’s cabinet—Secretary of State John Kerry, Secretary of Energy Ernest Moniz, and Treasury Secretary Jack Lew–and will convene on Thursday.