WASHINGTON -- Tighter borders and workplace enforcement alone will not solve the country's problem with illegal immigration and may make the situation worse by driving millions of people deeper in the shadows, U.S. Commerce Secretary Carlos Gutierrez said Wednesday. In testimony to the Senate Judiciary Committee on behalf of the Bush administration, the Cuban-born Gutierrez backed the Senate's comprehensive approach combining border security and new employer enforcement measures with a plan that gives many of the estimated 12 million illegal immigrants a path to citizenship. "The more this issue becomes one of enforcement only, we are driving them (illegal immigrants)...