Preserving world order is even harder. President Obama showed that kind of toughness in his United Nations address this week (you knew I was going to make this leap). It was one of the finest speeches of his presidency.

During his public life, Obama has hit the high notes of poetic romance — his 2008 campaign. He has also hit some prosaic notes of caution, realism and inaction. But this speech blended the two tones. It put tough-minded realism at the service of a high calling.

The speech was about defending the world order against enemies like ISIS and Putin. Breaking with past emphasis, he acknowledged that sometimes you have to use military might to fight off a military threat. He acknowledged that power-hungry thugs aren’t appeased if you try to show them how nonthreatening and reasonable you are. Obama cast off his cloak of reluctance and more aggressively championed democracy than he has recently. He was direct and forthright.