Sen. Arlen Specter on Thursday asked the Senate Ethics Committee to investigate whether a top aide improperly helped direct nearly $50 million in Pentagon spending to clients represented by her husband.

The Pennsylvania Republican asked for the review of legislative assistant Vicki Siegel Herson's actions after USA TODAY reported Thursday that his office inserted 13 provisions into spending bills benefiting clients of her husband, Michael Herson, a registered lobbyist. (Related stories: 6 clients got projects | Senate aide's spouse gets a windfall)

Specter, who is chairman of the Senate Judiciary Committee, said he believes he and Siegel did nothing wrong. He said neither Herson nor anyone from the firm he heads, American Defense International, had lobbied his office.

Specter acknowledged that he inserted the spending provisions - known as "earmarks" - into Pentagon budget bills as a member of the Senate Appropriations Committee. He said he didn't know the earmarks were going to Herson's clients.

Five companies and Drexel University, all represented by Herson, have received $48.7 million in earmarks during the past four years. Those six clients paid Herson's firm about $1.5 million from 2002 through last July, lobbying disclosure reports show.

Specter said he didn't know whether Siegel, who was his top appropriations aide until about six months ago, had recommended the earmarks to him.

"I don't think she would have made any recommendations where she knew her husband had a client involved," Specter said. "That would have been a blatant conflict of interest and inappropriate, and I don't think that happened."

Specter said he would ask his entire staff if any had relatives who were lobbyists. "I don't permit staffers to have relatives lobby the office," he said.

His chief of staff, William Reynolds, said in a statement that other lobbyists and company executives had requested the earmarks, not Herson's firm.

Siegel was one of his staff members who ordinarily would review the hundreds of requests for earmarks and recommend some for inclusion in the budget, Specter said. He added that Siegel reduced her work time to one day a week six months ago, so she could spend more time with her children.

Herson has said no one from his firm had lobbied anyone in Specter's office. Siegel did not respond to telephone and e-mail messages seeking comment.

Also on Thursday, Citizens for Responsibility and Ethics in Washington, a liberal-leaning watchdog group, sent a letter to the Senate Ethics Committee requesting an investigation into whether Siegel played a role in approving earmarks for her husband's clients.

Senate ethics rules prohibit senators and their staffers from using their positions to further their personal financial interests. USA TODAY found no evidence that Specter or Siegel broke ethics rules.

Reynolds' statement said two CEOs, representing Gestalt LLC and Power+Energy, contacted Specter's office directly to request earmarks for their companies. The statement said Universal Space Network used lobbyist Rob Bickhart to request its $2.5 million earmark.

Senate reports do not list Bickhart as a registered lobbyist for Universal Space Network. Bickhart could not be reached for comment. Reynolds could not be reached to explain the discrepancy.

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