Peter Bergen is CNN's national security analyst, a vice president at New America and a professor of practice at Arizona State University. He is the author of the new book , "United States of Jihad: Investigating America's Homegrown Terrorists." This piece was adapted in part from his book, "The Longest War."

(CNN) Occasionally Donald Trump says something that is politically incorrect but which also happens to be true.

On Tuesday at a campaign rally in North Carolina, Trump defended the former Iraqi dictator Saddam Hussein's record on terrorism, saying, "He was a bad guy -- really bad guy. But you know what? He did well? He killed terrorists. He did that so well. They didn't read them the rights. They didn't talk. They were terrorists. Over. Today, Iraq is Harvard for terrorism."

Defending the brutal Iraqi dictator who killed hundreds of thousands of his own people isn't exactly fashionable. But if you consider the 13 years of war that have wracked the country -- in which a quarter of a million have died -- and add that Saddam brutally repressed all dissent, including groups such as al Qaeda, and also add to this that ISIS is itself a fruit of the Iraq War, it's a far more defensible position.

Trump didn't offer any evidence for his assertions about Saddam's brutal repression of terrorist groups or of Saddam "killing terrorists," but his observations about the dictator are an implicit critique of the George W. Bush administration's erroneous claims before the Iraq War that Saddam was allied to al Qaeda. Those claims were an essential element of the case that the administration made to go to war, since Saddam's supposed connections to al Qaeda were the only purported evidence that he might give his putative weapons of destruction to terrorists.

The centerpiece of the Bush administration's case for going to war in Iraq was Secretary of State Colin Powell's presentation to the U.N. Security Council on February 5, 2003, six weeks before the invasion. Powell's presentation was a bravura performance that seemed to establish beyond a doubt that Saddam was actively concealing an ongoing weapons of mass destruction program and was in league with al-Qaeda.

At one point the secretary of state dramatically brandished a small vial of a white powder of supposed anthrax, saying "about this amount...shut down the U.S. Senate in the fall of 2001." As Powell gave his speech, sitting directly behind him was CIA director George Tenet, giving a visual imprimatur to what Powell was saying.

One section of Powell's UN speech tried to make the case for an emerging alliance between Saddam and al-Qaeda:

"Iraq today harbors a deadly terrorist network headed by Abu Musab al-Zarqawi, an associate and collaborator of Osama bin Laden and his al-Qaeda lieutenants...When our coalition ousted the Taliban, the Zarqawi network helped establish another poison and explosive training center camp, and this camp is located in northeastern Iraq... He traveled to Baghdad in May of 2002 for medical treatment, staying in the capital of Iraq for two months while he recuperated to fight another day."

Five weeks before the invasion of Iraq, CIA director Tenet testified before the Senate Armed Services Committee that Iraq had "provided training in poisons and gases to two al-Qaeda associates," a point that Powell had also made in his U.N. presentation.

What the American public did not know about Tenet's and Powell's crucial claim about Iraq training al-Qaeda associates on poison gases was that it didn't show a nexus between bin Laden, Saddam and some of the world's nastiest weapons. Instead, it was the tainted fruit of an "extraordinary rendition" in which militants were transported by American officials to countries that routinely used torture, where they would supposedly finally divulge whatever secrets they had been keeping from their American interrogators.

In December 2001 Ibn al Shaykh al Libi, a Libyan militant who had run an al-Qaeda-affiliated training camp, was captured in Pakistan. Libi told his FBI interrogators that there were no ties between Saddam and al-Qaeda. Several days into his interrogation the CIA then rendered Libi to Egypt, where jailors were known for subjecting their prisoners to beatings, electric shocks and sexual assaults.

To improve his chances of better treatment once in Egypt, Libi told his interrogators that bin Laden had sent two operatives to Iraq to learn about biological and chemical weapons.

Because Libi's story encapsulated the key arguments for the Iraq war, his tale was picked up by President Bush in a keynote speech in Cincinnati on October 7, 2002 in which he laid out his rationale for the coming conflict with Iraq, saying, "We've learned that Iraq has trained al-Qaeda members in bomb-making and poisons and deadly gases."

But once he was back in American custody, on February 14, 2004, Libi recanted what he had falsely told his Egyptian interrogators. Libi told his U.S. interrogators that he had "fabricated" his tale of the Saddam-al-Qaeda-poison connection to the Egyptians following "physical abuse and threats of torture."

Two and a half years into the Iraq war, in October 2005, the CIA released a report that finally disposed of the myth that Saddam and the leader of Al-Qaeda in Iraq, Zarqawi, had ever been in league, assessing that prior to the war, "the regime did not a have a relationship, harbor, or turn a blind eye towards Zarqawi."

Since the fall of Baghdad no documents have been unearthed in Iraq proving the Saddam-al-Qaeda axis despite the fact that, like other totalitarian regimes, Saddam's government kept meticulous records. The Defense Intelligence Agency had by 2006 translated 34 million pages of documents from Saddam's Iraq and found there was nothing to substantiate a "partnership" between Saddam and al-Qaeda.

Two years later the Pentagon's own internal think tank, the Institute for Defense Analyses (IDA), concluded after examining 600,000 Saddam-era documents and several thousand hours of his regime's audio and video tapes that there was no "smoking gun (i.e. direct connection between Saddam's Iraq and al-Qaeda.)"

In June 2008 the Senate Select Committee on Intelligence concluded, as every other investigation had before, that there was no "cooperative relationship" between Saddam and al-Qaeda. The committee also found that "most of the contacts cited between Iraq and al-Qa'ida before the war by the intelligence community and policy makers have been determined not to have occurred."

Also on Wednesday, after a seven-year investigation, the British inquiry into the Iraq War known as the Chilcot report was released. It found that before the war British intelligence repeatedly assessed there was no connection between Iraq and al Qaeda.

Trump is likely not a student of the English political philosopher Hobbes, who wrote his masterwork "Leviathan" in the shadow of the English Civil War. But he seems to have grasped Hobbes' main point: that an absolute "sovereign" (i.e. dictator) was preferable to "the war of all against all" that characterized the civil war in mid-17th century England as well as much of the civil war that continues to wrack early-21st century Iraq.

And Trump's claim that following the fall of Saddam, Iraq has emerged as the "Harvard" of terrorism is correct because Zarqawi in 2004 merged his terrorist group with al Qaeda to create "Al Qaeda in Iraq," which is the parent organization of today's ISIS.