The Senate Ethics committee is looking at whether Senator Bob Menendez acted improperly when he failed to disclose gifts from a political donor who is under investigation by the FBI.

Last fall an ethics complaint was filed by a New Jersey Republican State Senator alleging that in 2010 Senator Menendez failed to disclose trips to the Dominican Republic on a private jet belonging to a donor, as required. Last month, Menendez reimbursed the donor $58,000 dollars for the flights saying his failure to disclose the trips was an oversight.

The ethics committee is required to review any complaint that a senator may have violated the rules.

Of the 237 complaints made to the committee since 2008, just 37 resulted in a preliminary investigation. Those reviews, in turn  produced just a handful of so-called "letters of admonition" but no instances when sanctions were imposed. The last actual expulsion from the Senate was during the Civil war in 1862.

University of Minnesota Law Professor Richard Painter, an expert on the Congressional ethics process, says all too often the focus is on potential violations of Senate or House rules but not on what he sees as a growing ethical crisis.

"I am concerned that the ethics rules on travel and related matters can be window dressing to make the House and Senate look good when we have a very serious problem with the corruption of our political system with campaign money," he said.

In the last several years when the Senate Ethics Committee has sent one of its "Public letters of Qualified Admonition" to a member, the member has not sought re-election.  

In 2002, New Jersey Senator Robert Torricelli withdrew from his re-election bid when he was admonished for taking gifts from a donor who had been convicted of illegally funneling money into Torricelli's campaign accounts. In 1982, New Jersey Senator Harrison Williams resigned after being convicted on Federal corruption charges.

Senator Menendez is referring all media inquiries about his ethics review to the Senate Ethics Committee, which declined to comment. Historically, the panel's reviews take months to complete.