A leadership election to decide who will take over as chairman of the Senate Republican Policy Committee will take place June 25, a senior GOP aide said Wednesday.

The election will come a little more than a week after Sen. John Ensign (R-Nev.) announced he was stepping down from leadership’s No. 4 post after admitting that he had an extramarital affair. At a Las Vegas press conference Tuesday, Ensign admitted that he carried on an affair with a former campaign employee who was married to someone who worked on Ensign’s staff.

Sen. John Thune (S.D.), who currently serves as Conference vice chairman, is expected to announce his candidacy for Ensign’s former slot soon, according to several Republican aides.