Some 82 senators have signed a letter to President Obama laying out the terms of a final deal with Iran that they would find sufficient to relax U.S. sanctions. If the terms aren’t met, then the senators, many of whom supported the Menendez-Kirk sanctions bill that Majority Leader Harry Reid (Nev.) refused to bring to the floor, would demand a resumption of sanctions. The letter warns:

Sen. John McCain (R-Ariz.) addresses the American Israeli Political Action Committee (AIPAC) Conference in Washington this month. ( Jim Watson/Getty Images)

Should an acceptable final agreement be reached, your administration will need to work together with Congress to enact implementing legislation to provide longer term sanctions relief beyond existing waiver authorities – either through suspension, repeal or amendment of statutory sanctions. Should negotiations fail or Iran violate the Joint Plan of Action, Congress will need to ensure that the legislative authority exists to rapidly and dramatically expand sanctions. We need to work together now to prepare for either eventuality. . . . We must signal unequivocally to Iran that rejecting negotiations and continuing its nuclear weapon program will lead to much more dramatic sanctions, including further limitations on Iran’s exports of crude oil and petroleum products.

The letter sets out the principles that should be embodied in a final deal including: no right for Iran to enrich uranium; dismantling Iran’s nuclear weapons program and preventing it “from ever having a uranium or plutonium path to a nuclear bomb”; addressing the issues in “United Nations Security Council resolutions, including any military dimensions of its nuclear program”; and robust sanctions. The letter also makes clear that if Iran violates the interim deal, uses talks as a stalling tactic or walks away from the talks, “pressure will intensify.”

This comes in the context of the next round of Iran talks in Geneva and marks the first time the Senate has gone on record with a statement of the final terms of an acceptable deal. The Senate is insistent that it be involved in the outcome of talks and potential resumption of sanctions; no free hand will be given to the administration. The letter omits any mention of the potential for military action. Perhaps that is simply an effort to focus attention, for now, on the impending talks. Maybe it is simply recognition that no one believes the administration will actually act militarily.

Even this letter was too much for a number of Democrats. Senate sources tell me Sen. Carl Levin (D-Mich.) tried to stop its momentum with an alternative that focuses on enforcement of a potential deal. That suggests the White House is still loath to let Congress have its say. Certainly, the administration gives every sign that it is desperate to continue talks and avoid having to take more dramatic steps (economic or military) against the Iranian regime.

Two factors overshadow the administration’s evident desire to defer action in favor of endless, fruitless talks. First, Iran is unlikely to do any of the items listed in the letter. Pro-sanctions advocates in Congress will then have added justification for pushing Iran to the brink of economic collapse. Second, we’re arriving at the point at which the real barrier to Iran’s attainment of a nuclear weapons capability is Israel’s military. The rest at this point, especially given the administration’s lack of credibility, is noise.