Watch "Bush: Two Years Later," at 8 ET tonight on a "State of the Union" special.
(CNN) -- Former President George W. Bush defended his administration's handling of the war in Afghanistan on Sunday, telling CNN that some NATO allies who contributed troops to the conflict "turned out not to be willing to fight."
In an interview with CNN's Candy Crowley, Bush strongly refuted criticism that his administration took its "eye off the ball" in Afghanistan when he ordered troops to invade Iraq. He said he ordered American forces to overthrow Iraqi dictator Saddam Hussein with the assumption that allied forces would help make up the difference in Afghanistan.
"What happened in Afghanistan was that our NATO allies, some of them, turned out not to be willing to fight," Bush said. "Therefore, our assumption that we had ample troops -- U.S. and NATO troops -- turned out to be a not-true assumption. So we adjusted."
The former president didn't name any countries specifically from NATO, which includes 28 nations in Europe and North America. Some 785 military personnel from NATO countries besides the United States have been killed in Afghanistan since hostilities began in October 2001, with the United Kingdom, Canada and France having the most fatalities.
The comments by the 43rd U.S. president, along with those of his brother and former Florida governor, Jeb Bush, aired during a CNN special, "Bush: Two Years Later."
The former president addressed a host of matters in the interview, which came days after the release of his 481-page memoir, "Decision Points," and two days ahead of the groundbreaking for his presidential library and museum on Southern Methodist University's campus in Dallas, Texas.
Bush said he "felt terrible" that weapons of mass destruction were never found in Iraq, despite the administration's persistent and insistent case that Saddam Hussein had them before the invasion.
But while he took responsibility for the big push on and subsequent lack of WMDs, the former president said he still thought the Iraq war was justified.
"If (Saddam Hussein) was in power today, the world would be a lot worse off," he said. "I believe that a free Iraq will be transformative in the Middle East."
Bush said he had no regrets, too, about his decision near the end of his second term to push the 2008 federal bailout that loaned hundreds of billions of dollars to companies including AIG, Citigroup, Bank of America and General Motors.
President Barack Obama later successfully pressed to use billions more in federal funds to buttress the U.S. economy, as it struggled through what's been called "The Great Recession" marked by high unemployment and rounds of foreclosures in a percolating real estate crisis.
"I set aside my free market principles and made a very difficult decision," Bush said. "I believe that those decisions ... did prevent the economy from heading into a depression."
Bush said he was dismayed when his administration's efforts to efforts to change the Social Security system -- an effort to control its costs -- failed to bear fruit.
In late 2004 and early 2005, his administration laid out proposals to overhaul Social Security, in part by creating individual investment accounts that would act more like a traditional 401k and replace the current collective Social Security pool. But the plan floundered under pressure from Democrats and special interest groups such as the AARP, and Congress never even saw any formal legislation, much less voted on it.
"Not reforming Social Security was a huge disappointment," Bush said.
Jeb Bush joined his brother for part of the CNN interview, saying he never publicly disagreed with George W. Bush when he was president and is "not going to start now."
Alluding to the hyperpartisanship in Washington, the former Florida governor said there's still room for civility in politics.
"I don't think you can be against everything, just because someone has a D (for Democrat) by their name and you have an R (for Republican) by your name," Jeb Bush said.
George W. Bush said that he was mindful not to get involved in "name calling" as president, adding that he wasn't bothered when he was targeted. Bush said, too, that he didn't support Republicans challenging Democrats' patriotism just because they disagreed with them.
"I don't remember doing that personally, and that was uncalled for if that was the case," he said. "Patriotic people disagreed with my decisions."
One Democrat he has no qualms with is his Oval Office predecessor, Bill Clinton. Bush said he "genuinely liked" Clinton, whom he called one of his "buddies," in part because he's been so "gracious" to his father, George H.W. Bush.
The Bush brothers both said Republicans' setbacks in recent election among Latinos -- which voted Democrat by a 2-to-1 margin -- should be a top concern for the party, with George W. Bush calling the situation "un problemo."
"Part of it relates to tone," said Jeb Bush, saying some Latinos turned away from the Republican party when some of its members spoke strongly on illegal immigration. "If they don't feel welcome, they're not going to listen to the message."
Jeb Bush reiterated that he would not run for president -- like his brother and father -- in 2012. The former governor also said he did not want to head the national Republican party because he wanted to achieve "some financial independence" for himself and his family.
The current GOP party chief, Michael Steele, has faced persistent criticism from Sen. Jim DeMint, R-South Carolina, and others in recent months, even though Republicans scored big wins in the recent mid-term elections. As to speculation about Steele's future as the party's head, Jeb Bush opted not to wade into the party leadership debate, saying he was "Switzerland in relation to national Republican politics."
"If I'm trying to achieve financial security for my family and I'm not running for office," Jeb Bush said. "I certainly wouldn't run for RNC chairman."
Jeb Bush said that he could see either or both of his sons, Jeb and George, following their father, their uncle, their grandfather and their great-grandfather (former Sen. Prescott Bush of Connecticut) by running for political office. But George W. Bush said he didn't see his daughters, twins Jenna and Barbara, who turn 29 this month, going into politics.
"They will be involved in helping improve people's lives," Bush said. "But I doubt they'll ever run for public office."
As to his own future, and legacy, Bush said he was content to let his memoir and his decisions speak for themselves.
"I'm not trying to shape my legacy," he said. "I'm trying to provide data points for future historians."