Former US president George W. Bush urged his younger brother Jeb to aim for the White House in a 2016 campaign that could enshrine his family as America's ultimate political dynasty.

"He'd be a marvelous candidate if he chooses to do so," Bush said, when asked about Jeb's presidential prospects in an ABC News interview aired Wednesday on the eve of the dedication of his presidential library in Texas.

"He doesn't need my counsel 'cause he knows what it is, which is 'run,'" Bush said. "But whether he does or not, it's a very personal decision."

The elder Bush also set tongues wagging in the interview by speculating that Jeb Bush could even face former secretary of state Hillary Clinton, should she chose to make another run at the Democratic nomination.

"It would be a fantastic photo," Bush quipped, but warned that the likely 2016 field would not become clear until after the mid-term elections.

In the interview, Bush also said he remains "comfortable" with the decision to invade Iraq, even as a new spate of bloody violence hit the country and rocked politics in Baghdad.

"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," Bush said.

"But history will ultimately decide that, and I won't be around to see it.

"As far as I'm concerned, the debate is over. I mean, I did what I did. And historians will ultimately judge those decisions."

But he will give history a shove in Dallas on Thursday when he opens his presidential library, showcasing his self-image as a leader of a land under attack who made tough decisions that kept Americans alive.

From a steel beam twisted in the inferno of the World Trade Center, to footage of the twin towers collapsing in ash clouds, the September 11 attacks loom large over the museum of Bush's 2001-2009 administration.

Visitors will find an apt proxy for the man himself: the museum at Southern Methodist University pulses with energy and patriotism but Bush skeptics may find a lack of nuance and absence of self doubt.

Bush has chosen to ask a direct question of the tourists and historians of tomorrow: 'what would you have done in my shoes on terrorism and Iraq, Hurricane Katrina and the 2008 economic crash?'

The airy limestone building will be dedicated with President Barack Obama and all living ex-US presidents on hand.

Dignitaries will enter a "Freedom Hall" before viewing exhibits detailing Bush policy on issues like education and tax cuts.

But suddenly, they will turn a corner to confront a chunk of wreckage from Ground Zero and walls bearing names of 9/11 victims.

The story is of a president who thought he was going be occupied with domestic policy only to find himself defending the homeland from Al-Qaeda.

The centerpiece of the Bush library is an interactive exhibit known as "Decision Points Theater."

Bombarded by footage of breaking news, and offered short videos of "advice" from actors posing as officials and military top brass, visitors use touch screens to make their own decisions on the crises that defined Bush.

The ex-president then pops up on a screen to justify the real steps he took on four key issues, the invasion of Iraq and the subsequent troop surge, Katrina and the financial crisis.

Bush left office in 2009 as one of the most unpopular presidents in recent history, with a Gallup approval rating of just 34 percent.

Scholars polled by Siena College in 2010 put Bush in the bottom five of all US leaders.

His absence from the scene seems to have improved his image slightly: in a CNN/ORC poll Wednesday, 42 percent said Bush's presidency was a success.

But critics say Bush invaded Iraq on false pretenses, mismanaged the occupation and thereby weakened America's global power and moral standing.

The aftermath of Katrina in 2005 remains a masterclass in how not to handle natural disasters.

And Bush's failure to spot an onrushing financial meltdown led to the greatest recession since the 1930s.

Yet, former Bush aides hope the opening of the library will mark the first step in a reappraisal.

They look to presidents Harry Truman and Dwight Eisenhower, who limped out the White House but were later rehabilitated by history.

However, Professor Bruce Buchanan, a presidential scholar at the University of Texas, said Bush's reputation is out of his hands.

Transformations "haven't occurred after an effective PR effort by a president or his supporters," he said.