Census Director Robert Groves is a by-the-books statistician, but he recently made a heartfelt plea to a congressional subcommittee: If politics taint the census, "we're in deep trouble ... as a Census Bureau, as a census and as a country." Days later, politics were back in the forefront when that panel's ranking Republican came to Chicago to urge the census officials to end a partnership with the Service Employees International Union, which has traditionally backed Democrats. Partnering with the union "undermines the integrity of the census," said U.S. Rep. Patrick McHenry of North Carolina. From ACORN to illegal Immigration, the...