President Barack Obama has praised George W Bush at the dedication of the former president's library for showing strength and resolve in the days after the September 11 attacks and said if Congress passes immigration reform "it will be in large part thanks to the hard work" of his predecessor.
Mr Obama spoke along with all four living former presidents in a rare reunion honouring one of their own at the opening of the George W Bush Presidential Centre.
Mr Bush, the country's 43rd president, gave a closing speech with tears welling in his eyes."My deepest conviction, the guiding principle of the administration, is that the United States of America must strive to expand the reach of freedom," Mr Bush said.
"I believe that freedom is a gift from God and the hope of every human heart."