Republican support for immigration reform focuses mainly on political self-interest. Since 71 percent of Hispanics and 74 percent of Asians voted Democratic last November, it's easy to see why smart Republicans are so concerned.As Ron Bonjean, a prominent GOP strategist, told Reuters: "If Republicans refuse to pass comprehensive immigration reform, we will become obsolete as a party within 10 years."But there is another compelling reason for Republicans to get behind the immigration bill now on the Senate floor. That measure, which would eventually legalize millions of undocumented foreigners and attract thousands of highly educated scientists and entrepreneurs, strongly encourages economic growth.