Rumors are swirling that the United States and its international partners (known as the "P5+1") are on the verge of striking a final comprehensive agreement with Iran over the future of its nuclear program.

A good deal will limit Iran's uranium enrichment capacity, downgrade its plutonium production facility and impose a rigorous inspection regime that not only will keep watch over Iran's declared nuclear infrastructure, but also will guard against any covert activity. These three pillars will effectively block any path Iran has to building nuclear weapons.

We're encouraged that reports from the negotiations confirm that this is largely what the Iranians will agree to, in exchange for lifting the crippling sanctions imposed by the United States and the international community, which have been key in bringing the Iranians to the negotiating table.

Unfortunately, Iranian agreement isn't the only hurdle the Obama administration faces. It must also negotiate Congress, which is trying to insert itself in this process in a variety of unhelpful ways.

Case in point: Sen. Bob Corker, R-Tenn., is pushing a bill — cosponsored by a majority of Republicans and a handful of Democrats — under the guise of giving Congress the chance to officially "weigh in" on any final deal. While that seems a reasonable enough request, the bill contains various provisions that would hamstring the White House's ability to conduct diplomacy and could ultimately kill any agreement in its tracks.

For instance, the bill requires certifications on non-nuclear issues that have never been part of negotiations and that are meant to kill the deal's implementation. If certain certifications cannot be made, Congress would vote "up or down" on an agreement. Given the Republican 47's open letter to the Iranians, meant to undermine President Obama, one needn't have much imagination to understand how Congress would vote. And if Congress votes against an agreement, the whole thing could fall apart.

If Congress votes on poison-pill legislation or overrides a presidential veto, two scenarios may come to pass. First, the Iranians may be left wondering whether the United States can make good on its commitments and walk away. Second, our international partners may conclude that the U.S. is not interested in a deal with Iran and abandon the coalition that has been critical in pressuring the Iranians on this issue. Multilateral cooperation and the underlying sanctions for the regime could collapse.

In either instance, with the U.S. to blame for the breakdown in diplomacy Iran's nuclear program will be unconstrained and unmonitored, and a nuclear Iran will be open for business. Any subsequent actions taken to restart discussions would be significantly more difficult.

Supporters of the Corker measure must answer: What next? If diplomacy fails, military action remains the only alternative. But bombing would only temporarily set back Iran's nuclear capability. As one of the America's leading diplomats said: "The reality is that the Iranians have developed over the course of the last decade or more the know-how to enrich … and … you can't bomb it away."

The Obama administration, together with our closest NATO allies and other international partners, is pursuing the right approach in diplomacy. The American public agrees. A March CNN poll found that the majority of Americans back diplomacy. Congress will have a key oversight role in any nuclear deal, and it will eventually be asked to permanently lift nuclear-related sanctions in return for Iran's compliance with the agreement over time. However, now is not the time to meddle in this delicate process.

We appreciate that Minnesota's Sens. Amy Klobuchar and Al Franken have been supportive of diplomacy thus far. For the sake of U.S. national security and preventing a needless war, they should continue to advocate for diplomacy and urge their colleagues on Capitol Hill to do the same.

Phyllis Kahn, DFL-Minneapolis, is a member of the Minnesota House and a board member of Women's Action for New Directions. Sandy Pappas, DFL-St. Paul, is president of the Minnesota Senate, vice-president of the Women Legislators' Lobby and has 18 grandchildren living in northern Israel, two hours by plane from Iran.