At least twenty senators have backed an amendment that would stymie an IRS proposal that could allow other nations to more easily obtain data on nonresident bank clients in the United States. The provision, drafted by Sen. Marco Rubio (R-FL), is intended to prevent the agency from moving forward with a January 2011 plan to require U.S. banks to report annually on their foreign clients. The IRS proposal would reciprocate the data sharing the United States has asked of non-U.S. banks under the Foreign Account Tax Compliance Act (FATCA). Although intended to help other nations fight tax evasion, the IRS...