Republican presidential hopeful Mike Huckabee, seeking to blunt criticism of his record on immigration, has issued an extensive new plan that calls for illegal aliens to return home voluntarily, pushes employers to check workers' status and would end several legal immigration programs. It marks a major change in tone from Mr. Huckabee's tenure as governor of Arkansas, when he campaigned for illegal-alien students to be eligible for college scholarships and financial aid and complained about federal raids on work sites that employed illegal workers. In his book earlier this year, he also called for a way for illegal aliens to...