Senate Republicans on Sunday continued to avoid weighing in to whether Sen. John Ensign (R-Nev.), embroiled in a scandal, should stay on in the upper chamber.

The Senate Ethics Committee has opened a preliminary inquiry after the New York Times last week reported on efforts by Ensign to arrange lobbying work for Doug Hampton, a former staffer to the senator and husband of the woman with whom Ensign had an affair.

The paper suggested that some of the lobbying work may have been prohibited under a rule that bans lobbying for one year after an aide leaves a congressional office.

Sen. Barbara Boxer (D-Calif.), chairwoman of the Senate Ethics Committee, did not suggest which aspects of the report the committee would investigate.

"It's because I'm the chair of the Senate Ethics Committee that I can't discuss this with you, other than to say that there is a preliminary investigation going on and we will look at all aspects of this case as we do whenever there's a case before us and try to get to the bottom of it as quickly as we can, in fairness to all," Boxer said on CNN's "State of the Union."

Also appearing on CNN, Senate Minority Whip Jon Kyl (R-Ariz.) would not comment on Ensign's political future or whether the senator should remain in the upper chamber.

Kyl said he would "wait and see what happens" after the ethics committee proceeds.