Rick Santorum joined a bipartisan chorus this January in criticizing fellow Republican presidential candidate Mitt Romney for not releasing his tax returns, but 12 years earlier the former Pennsylvania senator faced similar criticism for refusing to disclose who paid for a family trip to Rome.In 1999 a Virginia-based nonprofit called the Common Good Foundation paid for Santorum and his wife, Karen, to spend six days in Rome, according to an article in The Philadelphia Inquirier on June 23, 2000.Santorum followed Senate protocol and filed paperwork showing that the organization, whose website says it is "a movement of faithful Christians dedicated to building a culture of life, family, freedom and solidarity," had paid for his trip.