Top national security officials have warned that prospects for a diplomatic solution between the U.S. and Iran could be undermined by legislation likely to reach the Senate floor in the immediate aftermath of the April 13-14 round of U.S.-Iran talks. The legislation pushes impossible preconditions for diplomacy and radically lowers the threshold for war. As early as next week, the Senate could vote on legislation that Col. Lawrence Wilkerson, former Chief of Staff for Secretary of State Colin Powell, said "reads like the same sheet of music that got us into the Iraq war, and could be the precursor for a war with Iran." Wilkerson has joined me in lobbying members of Congress and their staff against the legislation, pointing out that it is "effectively, a thinly disguised effort to bless war." Colin Kahl, who served as Deputy Assistant Secretary of Defense for the Middle East from 2009 until late last year, is another of the top national security officials who have blasted the legislation and the policy shift that it endorses. At a Capitol Hill briefing earlier this year, Kahl warned that this resolution and similar initiatives could "box in our negotiators from being able to find a diplomatic solution." The majority of Congress has ignored these warnings, and have endorsed ultimatums that if pursued, would make diplomacy virtually impossible. Ruling Out a "Nuclear Weapons-Capable" Iran = Code for War Without explicitly directing the administration to abandon diplomacy and prepare for war, the resolutions (S.Res. 380, H.Res. 568) produce nearly the same result by drawing the "red line" for military action against Iran at a nuclear weapons capability, not an actual weapon. House and Senate majorities' endorsement of "nuclear weapons-capable" as the new threshold for total "unacceptability" -- congressional parlance for military action -- begs the question: how does Congress define "nuclear weapons-capable"? After all, Congress is already calling on the administration to shift the U.S. "red line" from "nuclear weapons acquisition" to "nuclear weapons capability" not only in these non-binding resolutions, but also in the new sanctions package expected to reach the Senate floor soon. And yet these resolutions do not contain any definition of "nuclear weapons-capable," an increasingly politicized term that lacks any established technical definition, according to arms control experts. Senator Joe Lieberman (I-CT), a primary author of the legislation, has admitted there is such ambiguity that "everybody" could claim a different interpretation of the term. Iran has arguably crossed a threshold of "nuclear weapons capability" already, as Col. Richard Klass has explained, so these resolutions could be interpreted to endorse military action today. Paul Pillar, a CIA veteran on Middle East affairs, wrote an excoriating analysis of the legislation's litany of ultimatums, saying that "by declaring 'nuclear weapons capability' rather than acquisition of a nuclear weapon to be unacceptable, the resolution also blurs red lines in a way that may flash green lights to Israel to launch a military attack on Iran." In a letter to Congress, a broad coalition of 26 national organizations warned that by shifting the 'red line' to 'nuclear weapons capability', "Congress would needlessly open to the door to war based on a threshold that experts say could apply to numerous countries ranging from Brazil to Japan." Will Congress Sabotage Talks? So, what is the purpose of the upcoming talks between Iran and the P5+1 (U.S., U.K., France, Russia, China, Germany)? Is it to secure a diplomatic and inspections-based agreement that would prevent a nuclear-armed Iran and ensure that Iran's nuclear program is only used for peaceful purposes? Or are the talks meant to coerce Iran into total capitulation, giving up its nuclear program altogether? That's an ultimatum that many U.S. officials agree is a standard doomed to failure. Even the Israeli government is not requiring Iran to cease its uranium enrichment altogether as a precondition for the upcoming talks. Yet, Congress has endorsed this impossible demand -- among many others -- for talks with Iran. Pillar lays out a devastating critique of these ultimatums, explaining: