Jonathan Sumption assesses the US and UK’s constitutional models. He describes Britain's unwritten constitution as a political institution. The US Constitution is by contrast essentially a legal document. This has led Americans to address what should be political questions – such as the right to abortion – via the courts, rather than through politics. Britain, Lord Sumption argues, should learn from the United States be careful about which rights should be put beyond democratic choice.

The programme is recorded in front of an audience at George Washington University in Washington DC.

The Reith Lectures are presented and chaired by Anita Anand and produced by Jim Frank. Editor: Hugh Levinson