The historic Geneva deal to limit Iran's nuclear program is scheduled to go into effect later this month. Once it does, the world will be farther away from a devastating war and a nuclear-armed Iran. As U.S. Rep. Betty McCollum, D-Minn., rightly pointed out, "this initial deal is a triumph for engagement and tough diplomacy." However, the U.S. Senate could reverse that progress through a vote on new sanctions as early as this week, putting the United States and Iran on a collision course toward war.

For the first time in a decade, the Geneva deal presses pause on Iran's nuclear program, and presses the rewind button on some of the most urgent proliferation concerns. In exchange, the United States has committed to pause the expansion of its sanctions regime, and in fact rewind it slightly with limited sanctions relief. Imposing new sanctions now would be just as clear a violation of the Geneva agreement as it would be for Iran to expand its nuclear program.

That's why the Obama administration has committed to vetoing any such measures and has warned that torpedoing the talks underway could put our country on a march toward war. A recent, unclassified intelligence assessment concurred with the White House's caution, asserting that new sanctions "would undermine the prospects for a successful comprehensive nuclear agreement with Iran."

However, in an open rebuke of the White House, the intelligence community and the 10 Senate committee chairs who cautioned against new sanctions, Sens. Robert Menendez, D-N.J.; Chuck Schumer, D-N.Y., and Mark Kirk, R-Ill., have introduced a bill (S. 1881) to impose new oil and financial sanctions on Iran.

Supporters of this measure stress that new sanctions would take effect only if Iran violates the Geneva agreement or fails to move toward a final deal at the end of the six-month negotiation period. And some dismiss this congressional threat as toothless, given President Obama's vow to veto any sanctions legislation. But simply passing these sanctions would dangerously escalate tensions with Iran. U.S. Rep. Keith Ellison, D-Minn., put it best: "New sanctions stand to kill any hope for diplomacy."

Already, anti-Geneva-deal counterparts in Iran's parliament have responded with their own provocation, introducing legislation to require Iran to enrich near weapons grade if the United States imposes new sanctions.

Like the Senate sanctions bill, the Iranian parliament's legislation would have a delayed trigger. Like the Senate bill, the mere introduction of this reckless legislation isn't a violation of the letter of the Geneva agreement per se. But both bills risk restarting the vicious cycle of confrontation that has defined the U.S.-Iran relationship for decades.

Without a significant public outcry, support for this sanctions bill could potentially reach a veto-proof majority of 67 senators and 290 representatives in the House.

Minnesota could play an important role in this showdown between supporters of using hard-nosed diplomacy to avoid military action and reduce nuclear risk, and those who would upend sensitive negotiations and make war likely. About half of the senators have staked out their positions, but neither Sen. Amy Klobuchar nor Sen. Al Franken have yet taken a public stance.

Minnesota is one of just 10 states where neither senator has taken a public position on whether or not to sign onto sanctions that would sink the deal — and risk another war in the Middle East.

While some new-sanctions proponents are banking on partisan politics to earn support from Republicans, it would still take seven of the remaining 23 undecided Democrats, along with all Republicans, to reach a veto-proof majority. All eyes will be on those 23 undecided Democrats — including Klobuchar and Franken.

Sens. Klobuchar and Franken can help ensure that the United States and Iran stay on a diplomatic path by publicly opposing this new sanctions bill and urging their colleagues to do the same.

William Davnie retired in 2007 after 26 years in the Foreign Service and now lives in Minneapolis. During his career in the Foreign Service, he served as chief of staff in the office of provincial affairs in Iraq, working on the deployment of the "civilian surge." Kate Gould is the legislative associate for Middle East policy at the Friends Committee on National Legislation in Washington, D.C.