The extent to which the US relies on its courts to settle the most contested questions – segregation, abortion and the rights of individuals against the state – means that Barack Obama’s first Supreme Court nomination marks a defining moment for his presidency.

The political and policy importance of the Supreme Court makes the confirmation process intensely polarising. It has long been mired in the culture wars Mr Obama has pledged to move beyond – a pledge that his choice of Sonia Sotomayor is carefully calibrated to respect.