One lesson you better learn if you want to be in politics is that you never go out on a golf course and beat the President.

Lyndon B. Johnson (1908-1973) American politician, educator, US President (1963-69)

Comment (1964) to Larry O’Brien III
    (Source)

On the occasion of O'Brien beating Johnson by one stroke on a nine-hole golf outing. Noted by his father in his book, No Final Victories: A Life in Politics, ch. 8 "LBJ" (1974).

See Gracian.