Colleagues and friends of Sen. John McCain, R-Ariz., reacted to and mourned the passing of the longtime senator Saturday night, lauding him as an outstanding colleague, a true friend, and an American hero who had a profound effect on many.

Sen. Lindsey Graham, R-S.C., one of McCain’s best friends and top allies in the upper chamber, lamented that America and freedom had lost one of its “greatest champions” and that he lost his mentor with the death of the 81-year-old.