If the Senate Ethics Committee decides to review Sen. John Ensign (R-Nev.) after revelations that he had an affair with a campaign aide, attorneys familiar with the panel said it would likely focus on employment-related issues.

The Nevada Senator acknowledged last week that he had an extramarital relationship with Cindy Hampton, a former aide to his campaign and political action committee who is married to Doug Hampton, Ensign’s administrative assistant when the affair began.

Attorney Stan Brand, a former House counsel and white-collar criminal defense attorney, said that while an affair itself is not sufficient to spark an ethics investigation, the Senate committee could examine issues related to the Hamptons’ employment.

“The question is the conduct and what’s the relationship of the conduct to office,— Brand said. “These are people who worked for him, and there have been issues [reported in the media] surrounding the circumstances of their having been terminated or separated from service.—

In a June 11 letter to Fox News, Doug Hampton asserted that the affair, which began in December 2007, resulted in the firing of him and his wife.

“Senator Ensign’s conduct and relentless pursuit of my wife led to our dismissal in April of 2008,— states a copy of the letter, published by the Las Vegas Sun. However, Hampton acknowledged the affair continued until August 2008.

Neither Doug Hampton nor his Las Vegas-based attorney, Daniel Albregts, returned telephone messages left Monday.

The government watchdog group Citizens for Responsibility and Ethics in Washington said Monday that it will file a complaint with the Ethics Committee this week requesting an investigation of Ensign’s office.

CREW Executive Director Melanie Sloan said the complaint, which has yet to be finalized, will focus on employment practices governed by the Senate Code of Official Conduct.

“If the Hamptons, either one of them, were fired because the affair ended — and Doug Hampton has alleged that, that they were dismissed because of the affair — they should investigate,— Sloan said.

She added that the ethics panel should also examine any payments made from Senate funds to the Hamptons during that period to determine whether they were appropriate.

Attorney Lee Blalack said that while the ethics panel is likely to open a preliminary inquiry given CREW’s anticipated complaint, he questioned whether the Senate would find grounds for a full investigation.

“The Ethics Committee staff will look into it. That doesn’t mean it’ll go anywhere,— Blalack said. “Barring some new evidence that … suggests misuse of Senate funds or attempting to engage in some conduct that arguably implicates a law, I don’t think it is likely this will have much traction.—

“It is not a high burden for the Ethics Committee to have a preliminary inquiry,— added Blalack, a partner in the firm O’Melveny & Myers who participated in the defense for former Rep. Duke Cunningham (R-Calif.).

The Senate Ethics Committee, which does not comment on its activities, has not indicated whether it will take up an investigation.