US Republican presidential hopeful Mitt Romney has returned home from an eventful European tour. Considered his most important decision before the election, he is now turning his attention to choosing a vice-presidential candidate. He will choose from three candidates: Susana Martinez, the current governor of New Mexico; Kelly Ayotte, a senator from New Hampshire; and former candidate and now TV pundit, Mike Huckebee. Al Jazeera's Alan Fisher reports from Washington.