What is George W. Bush's only regret over invading Iraq?

Invading Iraq was the right decision, but former President George W. Bush does have one regret, he told CBS's Bob Schieffer on Face the Nation, in a wide-ranging interview Sunday that touched on brother Jeb Bush's potential presidential run, Bush 43's "love letter" to his father, and the controversial Iraq war.

“Do you have any regrets [about sending troops into Iraq]?” Schieffer asked. “I mean, do you ever feel that maybe it was the wrong decision?”

“No I think it was the right decision,” Bush said, but he said he regretted the rise of the Islamic State (ISIS) in parts of Iraq.

“My regret is that a violent group of people has risen up again. This is al Qaeda plus. I put in the book that they need to be defeated. And I hope we do [defeat them].”

After spending six years largely out of the limelight, former President George W. Bush is making the rounds to promote his new book, "41," an affectionate biography of his father. Along the way, he's opened up to major networks and newspapers, offering surprisingly candid thoughts on his brother Jeb, his father grief over the second term he never had, and his advice to President Obama after the crushing Democratic defeat of last Tuesday's midterm.

But first, Bush had more to say about ISIS, including a thinly veiled jab at Obama's policy decisions in Iraq.

Though he has generally declined to critique Obama's presidency, Bush did write in his book that he regretted "subsequent developments and decisions" after he left office that contributed to the rise of ISIS, which threatened Iraq's struggling democracy.

"For the sake of our security and the Iraqi people, I hope we will do what it takes to succeed," he writes.

Bush also said that he was surprised that in 2003 Saddam Hussein did not abandon his country and leave when the United States threatened to invade.

“I thought there was a chance, yeah, I certainly hoped so,” Mr. Bush said. “But he didn’t. And so that’s why I put in the book, he chose war, twice.”

He also weighed in on the midterm election and commiserated with Obama on one point. 

“It’ll be fascinating to watch the level of cooperation develop, and I hope it does,” Bush said in an interview that aired Monday on NBC’s “Today” show. “The other thing is, people get kind of tired of a president after awhile — I’m a pro.”

He echoed that sentiment in his book, writing, "There's a reality about every two-term presidency: Toward its end, Americans grow weary of the president," adding in parentheses, "(Tell me about it!)"

Given that the author and subject of "41" are two related American presidents, the book reopens conjecture about a potential presidential run for Jeb Bush. The book also highlights the impressive Bush political dynasty.

And Bush hasn't been shy about speaking up on whether brother Jeb will run for president in 2016.

"I think he'd be a superb president and I think he'd be a very good candidate and I think he could heal wounds," Bush told USA Today. "Dad very much wants him to run, Mother, of course, has had a different point of view."

Still, Bush says he would "be all out" in campaigning for Jeb. "If he wants me to, I'd be helping him as best I can."

Jeb might need all the help he can get, according to the Monitor's Brad Knickerbocker.

"If the race ends up being dynasty-versus-dynasty (and the election was held today), Jeb Bush would have a challenge," he writes. "In the Real Clear Politics polling average, he trails the former secretary of state [Hillary Clinton] by 10 percentage points. But among Republicans thinking about their party’s nomination, he’s neck-and-neck with Sen. Rand Paul for the top spot."

As it turns out, for Jeb Bush, being a member of the Bush dynasty could be a double-edged sword.