BY JONATHAN STEMPEL

an 23 (Reuters) - Dinesh D'Souza, a conservative commentator and best-selling author, has been indicted by a federal grand jury for arranging excessive campaign contributions to a candidate for the U.S. Senate.

According to an indictment made public on Thursday in federal court in Manhattan, D'Souza around August 2012 reimbursed people who he had directed to contribute $20,000 to the candidate's campaign. The candidate was not named in the indictment.

Attempts to reach D'Souza and a lawyer representing him were unsuccessful.

D'Souza was charged in the indictment with one count of making illegal contributions in the names of others, and one count of causing false statements to be made.

Federal law in 2012 limited primary and general election campaign contributions to $2,500 each, for a total of $5,000, from any individual to any one candidate.

"As we have long said, this Office and the FBI take a zero tolerance approach to corruption of the electoral process," the U.S. Attorney for Manhattan, Preet Bharara, said in a statement released by the Federal Bureau of Investigation. Bharara is an Obama appointee.

Born in Mumbai, India, D'Souza, 52, is a former policy adviser to President Ronald Reagan, and has been affiliated with conservative organizations such as the American Enterprise Institute and the Hoover Institution at Stanford University.

He also directed a 2012 film critical of President Barack Obama, "2016: Obama's America," and has written books including "The End of Racism," "Life After Death: The Evidence" and "Obama's America: Unmaking the American Dream."

D'Souza campaigned in 2012 on behalf of Wendy Long, a lawyer and Republican who sought to unseat Democratic incumbent Kirsten Gillibrand as New York's junior senator. Long graduated from Dartmouth College in 1982, a year before D'Souza.

Long could not be reached for comment on Thursday.

Gillibrand, herself a 1988 Dartmouth graduate, ended up winning re-election to her first full term, collecting close to 72 percent of the vote.

In late 2012, D'Souza resigned his post as president of King's College, a small Christian college in New York City, after admitting he had become engaged to a woman even though he was legally married, though separated from his wife. He has been an outspoken defender of traditional marriage.

The case is U.S. v. D'Souza, U.S. District Court, Southern District of New York, No. 14-cr-00034. (Reporting by Jonathan Stempel; Additional reporting by Emily Flitter; Editing by Eddie Evans, Toni Reinhold)