WASHINGTON - The debate over immigration stretched from the White House to the West Coast on Saturday as thousands of demonstrators protested proposals to crack down on illegal immigrants. President Bush, in addressing an issue that has divided his party, underscored America's immigrant history and called for secure borders and strict immigration enforcement. Bush also urged Congress to write new immigration law with a guest worker program that could provide legal status — short of citizenship — for some of the estimated 12 million undocumented immigrants in the United States. "As we debate the immigration issue, we must remember there...