(CNSNews.com) – Federal prosecutors are reviewing a request for an investigation into whether Andy Stern, president of the Service Employees International Union (SEIU), violated the Lobbying Disclosure Act for his frequent visits to the White House and with members of Congress in 2009.

Americans for Tax Reform (ATR) and its subgroup the Alliance for Worker Freedom (AWF) sent letters to acting U.S. Attorney Channing D. Phillips of the District of Columbia asking for a probe.

“Specifically, it is important to determine whether those and related activities could constitute ‘lobbying’ by Mr. Stern in violation of the Lobbying Disclosure Act,” said the Nov. 13, 2009, letter signed by ATR President Grover G. Norquist and AWF Executive Director Brian M. Johnson...