The U.S. Supreme Court agreed Tuesday to take up the Obama administration's proposed new immigration plan that could shield more than four million people from deportation. If the court rules by this spring in favor of the White House, President Obama could begin putting the changes into effect during his final months in office. But if the administration loses, court battles could keep the program on hold for several more years. The new policy would allow adults here illegally to remain if they have children who are US citizens or lawful permanent residents. It would also expand a program, begun four years ago, that allows young people to remain in the US if they were brought here under age 16, provided they meet educational or military service requirements.