Republicans in the US will begin voting this week to choose their presidential candidate for November's election.<br /><br />The vast majority of the country will pick contenders in primaries, by means of a secret ballot. <br /><br />But in 14 states voters will meet in noisy, raucous political assemblies, where they will argue for their candidates and then gather for a speedy vote.<br /><br />The elections are called caucuses. And the first and biggest of these - to take place in Iowa on Tuesday - might just determine who runs for the White House. <br /><br />But critics of the process have argued that caucuses are flawed and outdated.<br /><br />Al Jazeera's John Hendren reports from Washington DC.
