Rep. Nancy Mace (R-S.C.) is "strongly considering" a run for U.S. Senate following the sudden death of Sen. Lindsey Graham (R-S.C.), two sources familiar with her thinking told Axios. Driving the news: Graham passed away late Saturday from "a brief and sudden illness," his office announced in a statement early Sunday morning. South Carolina Gov. Henry McMaster will be able to appoint an interim replacement to serve out the remainder of Graham's term through Jan. 3. But Graham was up for…