President George W. Bush tried to counter strong opposition among many Republicans to his guest-worker plan on Saturday, arguing that allowing immigrants to take jobs Americans don't want adds to "economic vitality." Bush weighed in on the immigration issue in his weekly radio address as the Senate was days away from taking up debate on the subject. The president favors including a temporary work visa in broad legislation that would also bolster border enforcement. But some Republicans view the guest-worker plan as a back-door amnesty for illegal immigrants and prefer an approach that focuses solely on toughening border security and...