Washington ? President Bush urged lawmakers on Saturday to come together on the complex and emotional issue of immigration, calling it “a critical challenge” now before the nation.

“We need a system where our laws are respected. We need a system that meets the legitimate needs of our economy. And we need a system that treats people with dignity and helps newcomers assimilate into our society,” he said in his weekly radio address. “We must address all elements of this problem together, or none of them will be solved at all.”

There are an estimated 12 million illegal immigrants in the country, and passions run high on what to do about them. Bush wants to establish a temporary worker program for some of them and create a path to citizenship – albeit a difficult one – for many. He says it is unrealistic to propose that millions of people be deported.

What he likes to call comprehensive immigration reform was once Bush’s top domestic priority.

But the president was stymied by members of his own party, who controlled Congress until January. While business and industry are demanding more low-wage workers, many conservatives reject the president’s approach as putting the interests of illegal immigrants before those of American workers.

He gave that effort a renewed push by devoting his radio address to the topic, and making it the subject as well of a commencement speech he was giving Saturday afternoon at Miami Dade College in Florida.