Having secured victory in the five latest Republican primaries, Mitt Romney has launched his campaign as the party's presumptive presidential nominee.<br /><br />Tuesday's wins in Connecticut, Delaware, New York, Pennsylvania and Rhode Island put the former Massachusetts governor in a nearly unbeatable position with 824 of the 1,144 delegates needed to be declared his party's nominee. <br /><br />Al Jazeera's Alan Fisher reports from Washington.
