Returning from an ill-received trip abroad, Mitt Romney, presumed Republican nominee for US presidency, must now turn his attention to nominating a vice-presidential candidate ahead of this month's Republican National Convention in Florida.

This will be Romney's most important decision before the election. Former vice president Dick Cheney criticised John McCain's selection of four years ago when he named the relatively inexperienced Alaska governor, Sarah Palin.

Al Jazeera's Alan Fisher reports from Washington.