But I tell you the New Frontier is here, whether we seek it or not. Beyond that frontier are the uncharted areas of science and space, unsolved problems of peace and war, unconquered pockets of ignorance and prejudice, unanswered questions of poverty and surplus. It would be easier to shrink back from that frontier, to look to the safe mediocrity of the past, to be lulled by good intentions and high rhetoric — and those who prefer that course should not cast their votes for me, regardless of party. But I believe the times demand new invention, innovation, imagination, decision. I am asking each of you to be pioneers on that New Frontier. My call is to the young in heart, regardless of age — to all who respond to the Scriptural call: “Be strong and of a good courage; be not afraid, neither be thou dismayed.” For courage — not complacency — is our need today — leadership — not salesmanship. And the only valid test of leadership is the ability to lead, and lead vigorously.

John F. Kennedy (1917-1963) US President (1961-63)
“The New Frontier,” Presidential Nomination Acceptance Speech, Democratic National Convention, Los Angeles (15 Jul 1960)