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.