"The purpose of a preliminary inquiry is to determine whether there is credible evidence that a violation within the Committee's jurisdiction has occurred."Politico notes the significance of a special counsel appointment, citing the special counsel investigation of former Speaker of the House Newt Gingrich in 1997. This does not appear to be a perfunctory hire by the Ethics Committee, and since they are enlisting a special counsel, the committee must feel there is some substance to Ensign's case.
While Ensign was cleared by the Justice Department in December, the Senate committee has yet to reach a verdict. Regardless of the final verdict, it's encouraging to see the Senate investigate its membership and not let possible ethics violations be swept under the rug.