Asked at a NATO meeting in France in April whether he believed in American exceptionalism, the president said, “I believe in American Exceptionalism just as I suspect that the Brits believe in British exceptionalism and the Greeks believe in Greek exceptionalism.” In other words, not so much.

The Obama administration does seem to believe in another kind of exceptionalism — Obama exceptionalism. “We have the best brand on Earth: the Obama brand,” one Obama handler has said. What they don’t seem to realize is that once you’re president, your brand is America, and the American people expect you to defend us against lies, not embrace or ignore them. We also expect you to know your history…

The White House ought to take a lesson from President Harry Truman. In April, 1950, Truman signed National Security Council report 68 (NSC-68). One of the foundational documents of America’s Cold War strategy, NSC-68 explains the danger of disarming America in the hope of appeasing our enemies. “No people in history,” it reads, “have preserved their freedom who thought that by not being strong enough to protect themselves they might prove inoffensive to their enemies.”

Perhaps Mr. Obama thinks he is making America inoffensive to our enemies. In reality, he is emboldening them and weakening us. America can be disarmed literally — by cutting our weapons systems and our defensive capabilities — as Mr. Obama has agreed to do. We can also be disarmed morally by a president who spreads false narratives about our history or who accepts, even if by his silence, our enemies’ lies about us.