SAN FRANCISCO -- The Obama administration has repealed a rule that would have threatened employers with prosecution unless they fired workers whose Social Security numbers did not match entries in a government database, ending a two-year battle in a San Francisco federal court. Although the Department of Homeland Security formally withdrew the "no-match" rule Wednesday, the administration is supporting another program enabling employers to check workers' names against electronic records that are supposed to screen out illegal immigrants. That program, E-Verify, is voluntary for most employers but mandatory for the 170,000 companies holding federal contracts and for their subcontractors. This...