President Barack Obama and Secretary of State John Kerry put a great deal of faith in their Iranian interlocutors, chief among them Iranian Foreign Minister Mohammad Javad Zarif. After all, Supreme Leader Ali Khamenei decreed that the negotiations should occur between foreign ministers, and if there has been one consistent pattern in the current negotiations, it is that Obama is unnervingly deferential to the Supreme Leader’s red lines.

Too often, presidents enter the Oval Office convinced that the failure of diplomacy rests more with their predecessors than with their adversaries. Obama is no exception. The State Department meanwhile has not, in the last half century at least, conducted a lessons-learned exercise to determine why its high-profile engagement diplomacy with rogue regimes—North Korea, Saddam’s Iraq, the PLO, the Taliban, or Iran—never seems to work. All too often, it seems history repeats.

It’s worth considering, then, what happened the last time the United States negotiated in earnest with Zarif. In the run-up to the 2003 Iraq War, both Zalmay Khalilzad (at the time a senior National Security Council official) and Ryan Crocker (then a Deputy Assistant Secretary of State), traveled to Geneva to meet secretly with Zarif. Their goal was to come to an understanding with Iran ahead of the start of hostilities commencing with Saddam Hussein’s Iraq: Basically, the U.S. side sought not interference and non-intervention with Iran. Zarif readily agreed that Iran would not interfere with any American pilots who strayed into Iraqi airspace, nor would Iran interfere in Iraq by inserting Islamic Revolutionary Guard Corps or Iranian-backed militias into the country.

Just days later, Operation Iraqi Freedom commenced and almost immediately, more than 2,000 Revolutionary Guardsmen and militiamen infiltrated into Iraq. The Iranian movement was reported first by an Iranian journalist close to former President Mohammad Khatami. In other words, Zarif gave his firm commitment that Iran would not conduct an action, and then Iran subsequently and blatantly violated that agreement.

There are two possible explanations: The first is that Zarif lied. The second is that the then-UN Ambassador was sincere, but he had no power to force groups like the Revolutionary Guards to abide by his negotiated commitments. Either way, the result was the same: Hundreds of Americans died because senior diplomats and the Bush administration chose to trust the Iranians.

The stakes with Iran are even higher today; perhaps it’s time for Kerry to explain in precise detail how it is that a man whose word was without meaning a decade ago has become a trusted intermediary. No one should hold their breath, however, because there is no good answer.