I trust you, so don't screw it up.

Those were President Barack Obama's instructions to then deputies Secretary of State William

Burns some years ago, but how he was to handle secret back-channel talks to negotiate a nuclear

deal with the government of Iran.

And Burns did his best, flying off on unmarked airplanes to Oman to meet with his Iranian

counterparts, and in New York ducking into service elevators and hotel stairways to

avoid the prying eyes of the press.

But in the end, Burns delivered, negotiating a landmark agreement with the Iranians for

them to sharply constrain their nuclear program in exchange for a gradual lifting of international

sanctions.

We had achieved our objectives and we diverted a potential path to war Burns writes in his

new memoir of the back-channel, or at least so we thought.

Today, much of Burns' work seems to be going up and smoke.

President Trump has backed out of the deal that Burns worked so hard to craft, and as

the U.S. imposes new sanctions on the Tehran regime, the Iranians have responded, firing

on oil tankers, shooting down a U.S. drone, and vowing to boost its stockpile of low-enriched

uranium beyond the limits set in the nuclear pact.

What does Burns' make of Trump's repudiation of everything he tried so hard to accomplish?

And what about the President's dealings with Vladimir Putin's Russia, where Burns

once served as ambassador?

We'll ask Burns himself, and we'll talk to one of our Yahoo News' colleagues, Alex

Nazarian about his new book, The Best People on President Trump's Cabinet, on this episode

...