Black maintained his interest in politics even after leaving office. He was a delegate to the 1904 Republican National Convention, and nominated President Theodore Roosevelt for election to a full term. Later that year, he was a candidate for the Republican nomination for United States Senator, but withdrew in favor of incumbent Chauncey Depew, who went on to win reelection. In 1908, Black, who had fallen out with Roosevelt, supported Charles Evans Hughes for president over Roosevelt's choice, William Howard Taft.