Caucus

Caucuses are generally homely low-tech affairs

A private meeting of party members designed to seek agreement on delegates for a state or national nominating convention based on which candidate they wish to support

Participants in presidential caucus meetings generally elect delegates to county conventions who in turn, at a later date, chose delegates for a state or local congressional convention.

The delegates selected are not bound, but usually follow the wishes of caucus-goers.

It is at these later meetings that the delegates will usually be chosen for the party's national nominating convention at which the presidential candidate will be declared.

Critics of the caucus system argue its laborious nature tends to mean it is dominated by political activists, unrepresentative of popular feeling, who will nominate candidates with little real chance of winning.

Just under a dozen states use the Caucus system - the number is different according to party.

Selection on the Republican side is done with a straw vote of those attending. Democratic caucus-goers express their preference through a show of hands, a sign-in sheet or by dividing themselves into groups according to candidate.