There is widespread agreement in Washington that Iranian acquisition of nuclear weapons is unacceptable and that all options should remain on the table to prevent this outcome. There is also a broad consensus that an enduring diplomatic solution to the nuclear crisis is preferable to military action against Iran — a step that would delay but not end the country’s nuclear program and could unleash further instability in an already tumultuous region. Both an Iranian bomb and bombing Iran could prove disastrous, but with each passing day, Tehran’s continued nuclear progress brings us closer to one of these two futures.

The surprising June 14 election of moderate Hassan Rouhani, a former nuclear negotiator who campaigned on improving Iran’s economy and relations with the world, as Iran’s new president may provide an opportunity to move beyond the nuclear impasse. Indeed, in many respects, Rouhani’s election represents a repudiation of the policy of “resistance” on the nuclear program pursued by Supreme Leader Ayatollah Ali Khamenei and outgoing President Mahmoud Ahmadinejad, which has produced Iran’s growing isolation and its economic devastation.

But a number of narratives and policies taking hold in Washington, especially on Capitol Hill, could squander this opportunity, making the least desirable outcomes — a nuclear-armed Iran or another war in the Middle East — more likely.

Opponents of engaging Iran have already deemed the election worse than irrelevant, accusing Rouhani of being a wolf in moderate sheep’s clothing. These critics accuse Rouhani, who has held senior positions in the Iranian government for decades, of complicity with a series of regime actions, including the 1994 bombing of an Argentina Jewish Center and the crackdown on Iranian students in 1999. According to this view, Iran’s new president is simply a more pleasant face on an evil regime — a tyranny that must be confronted and not negotiated with.