The American Federation of Government Employees is stepping up its campaign against House Republicans who want to further freeze federal pay to cover the cost of a payroll tax extension. AFGE this weekend will launch a nationwide series of television and print ads titled “Explain It To Me, GOP,” that wonder how cutting federal pay and benefits will help the economy recover. The ad seeks to put a face on federal employees who lawmakers often discuss in general — and sometimes disparaging — terms. It features members of AFGE locals — a Minnesota Veterans Affairs Department nurse, an electronics worker…