It seems George W. Bush still can't admit he's ever made a mistake -- even when one cost the lives of several hundred thousand people.

As his presidential library and museum open, former President George W. Bush said he remains "very comfortable" with perhaps the most controversial decision of his presidency -- the invasion of Iraq -- as he pursues a post-presidency removed from the spotlight but active on a series of core issues.

In a wide-ranging interview that touched on everything from his brother Jeb Bush's presidential prospects, the Republican Party's future, and his new passion for painting, he told ABC News' Diane Sawyer he hopes the library and museum serve as resources for historians to judge him based on the same facts he had access to as president.

That includes his decision to invade Iraq, despite the fact that the world later learned that Saddam Hussein did not have weapons of mass destruction. The museum presents that information directly, Bush said.

"We're just laying out the facts. And that was a fact," Bush said. "I am comfortable in the decision-making process. I think the removal of Saddam Hussein was the right decision for not only our own security but for giving people a chance to live in a free society. But history will ultimately decide that, and I won't be around to see it.

