LAURA BARRON-LOPEZ: In 2003, the U.S. invasion of Iraq was based on the allegation that the country's longtime dictator Saddam Hussein had weapons of mass destruction.

The failure to find these weapons prompted intense scrutiny of the decision to go to war over two decades ago.

In his new book author Steve Coll pored over hundreds of audio tapes and transcripts, many previously unreleased of Saddam Hussein's internal meetings.

To uncover his view on the tumultuous relationship with the United States, Nick Schifrin, recently sat down with Coll.

NICK SCHIFRIN: The U.S. relationship with Saddam Hussein evolved dramatically across the decades from the 1980s, when the U.S. aided his regime to the 90s when the U.S. sought to contain him, and dismantle his program of weapons of mass destruction.

And of course, after 9/11 the U.S. invasion and his death in 2006.

Using previously unreleased materials, the Achilles Trap, Saddam Hussein, the CIA and the Origins of America's Invasion of Iraq, tells the story of how Saddam Hussein and four successive U.S. administrations repeatedly misinterpreted each other.

The author is Steve Coll.

Steve Coll, thank you very much.

You write this book, in part is about the U.S. failure to comprehend Saddam Hussein and you write the U.S. thinking was often wrong, distorted and incomplete.

How sell?

STEVE COLL, Author, "The Achilles Trap": Well, Saddam's motives confounded us, they also confounded many of his own generals and his neighbors, but he took actions that just didn't fit into western logic and analysis.

And so the U.S. particularly after the war, to expel him from Kuwait, just assume the worst.

And in fact, he was making very complicated decisions on the basis of a calculation that we didn't really understand.

NICK SCHIFRIN: And that was mutual you right, how Saddam Hussein misinterpreted and had misaligned perceptions about what the CIA was doing.

How so?

STEVE COLL: Well, he saw the CIA is omniscient, and he had long experience with their involvement in changes of government in Iraq.

And he saw them around every corner and thought, for example, that they knew that he didn't have weapons of mass destruction.

And so he interpreted the accusation that he did, as just a game and his comments to his comrades when he was talking to them in private was, there's no reason for us to play this game.

We are not going to be rewarded by being honest or cooperative.

So let's maintain our pride and defy them.

NICK SCHIFRIN: You document how the Reagan administration decided to help him writing at one point that by 1983, it had lashed itself to an ambitious dictator.

How did that effort go?

And how did Saddam Hussein's own perception of US assistance evolve?

STEVE COLL: Well, our objective was to help him avoid losing the war, he had started with Iran.

And we feared that he might and that Ayatollah Khomeini would expand the Iranian Revolution into Baghdad.

So we started providing him with secret intelligence to give him a military advantage.

He always regarded this help with suspicion, and he thought we were playing a double game.

And we assured him for several years that he was wrong.

And then in 1980 -- NICK SCHIFRIN: He wasn't wrong.

STEVE COLL: He wasn't wrong.

And the Iran Contra scandal demonstrated that at least for a short time, the Reagan administration had played both sides.

And there are these wonderful tapes after the scandal is revealed where he says to his comrades, I told you so.

And what's important about it is that this conviction that there was a conspiracy between the United States Israel and Iran against him, persisted well into the 90s.

And so later, as he's talking to his colleagues about whether to cooperate he refers back to Iran Contra and says, just remember, what was revealed then remains the case now and so we should be careful.

NICK SCHIFRIN: How did Saddam Hussein undergo what you describe as the quote stunning transformation from tenuous American ally to mortal enemy?

STEVE COLL: By invading and occupying Kuwait innocent neighbor with no defenses that a country he decided essentially, in the aftermath of his very expensive war with Iran that he needed Kuwait's wealth to reconstruct Iraq.

And he ended up in a dispute with the Kuwaiti royal family and then decided basically to sack the country.

Of course, George H.W.

Bush organized an international military coalition to successfully expel him from Kuwait.

But he survived in power.

And that became the unfinished business of the 1990s that George W. Bush inherited on 911.

NICK SCHIFRIN: What did you discover about why Saddam Hussein essentially destroyed his weapons of mass destruction program after the Gulf War, but then was reluctant to allow you and weapons inspectors to be able to confirm that fact.

STEVE COLL: In the summer of 1991, he more or less secretly destroyed his chemical and biological stocks and the infrastructure of his nuclear weapons program.

But then he failed to keep any records.

He failed to tell the truth about what he had done.

He lied about the history of the program.

And he didn't really come clean for four or five years creating the impression that he was hiding a secret weapons program.

And that uncertainty persisted right through to the end.

Why?

Partly, I think he didn't want to appear weak in front of his enemies.

He didn't want to appear weak in front of his own generals, because he feared a coup attempt.

He didn't want to be humiliated.

And he also concluded that honestly wouldn't pay.

And about this, he might be right, because as Madeleine Albright announced in 1997, the real underlying policy of the sanctions he was trying to escape was not justice, disarmament, but his replacement.

NICK SCHIFRIN: The third era that you write about, of course, is after 911.

And you point out in the days after 9/11, he made no attempt to separate himself from Osama bin Laden and said publicly, the U.S. quote is reaping the thorns, its leaders have planted explain that.

STEVE COLL: He was oblivious to his own vulnerability after 911.

And like a lot of people in the Arab world, he thought that the United States deserved a little bit of taste of the kind of rebound of its foreign policy.

And so he became this kind of pundit in his meetings with his own cabinet and with visitors continually talking about America's failures in the world and the consequences of 911.

At the same time, he really was slow to pick up on the possibility that he would be targeted in retaliation from 9/11.

And he would say, of course, it had nothing to do with Osama bin Laden.

I'm against Islamists of that type.

But he didn't recognize that he was already in the crosshairs.

NICK SCHIFRIN: And finally, this is not about Ukraine about the Middle East is a different topic than you've written out before.

Why this topic?

Why this book?

STEVE COLL: Well, I hope that enough, time has passed that this momentous event in American post-cold war life, the Iraq War, probably the biggest pivot point that we experienced as a nation after the fall of the Berlin Wall, that we could think in a different and larger way about its origins because Saddam's contribution to the origins The war has been missing from our own reckoning.

And for once we have the opportunity with these new materials to really expand our sense of where this tragedy came from.

NICK SCHIFRIN: The book is called "The Achilles Trap, Saddam Hussein, the CIA and the Origins of America's Invasion of Iraq."

Steve Coll, thank you very much.

STEVE COLL: Nick, great to be with you.