We have real enemies in the world. These enemies must be found. They must be pursued and they must be defeated.

Campaigning is different from governing.

One of the things that you learn, having been in this [President's] office for four years, is the old adage of Abraham Lincoln's. That with public opinion there's nothing you can't do and without public opinion there's very little you can get done.

It was young people who stubbornly insisted on justice, stubbornly refused to accept the world as it is that transformed not just the country but transformed the world.

America is a strong and resilient country. And I know we will succeed, if we put aside partisanship and politics and work together as one nation.

Around the world, Gandhi, Nelson Mandela -- what they did was hard. It takes time. It takes more than a single term. It takes more than a single president. It takes more than a single individual.

The UK is an extraordinary partner for America and a force for good in an unstable world. I hope it remains strong, robust and united.