Nevada and Colorado both offer measures that would legalise possession of up to 28 grams of marijuana by anyone 21 and older. A measure in Rhode Island would restore voting rights to felons on probation and parole.

In Michigan, voters will decide whether to bar the state from using affirmative action to determine who gets into college, who gets hired and who receives contracts. The measure, which comes just weeks before the US Supreme Court is to hear arguments in two cases that could mean big changes in federal affirmative action law, is opposed by the Democratic and Republican governor candidates and a slew of business, labour, educational and religious groups. But recent polls indicate it has a chance.