President Obama reminded the nation that the United States is not at war with Islam, but only with violent fundamentalism. Such fundamentalism is not only Islamist — witness the recent shooting at a Planned Parenthood clinic in Colorado Springs.

Hawks want to declare World War IV against what they call “Islamic radicalism” and use ground U.S. troops to destroy the Islamic State in Syria and Iraq. But I.S.I.S. arose in response to the U.S. invasion of Iraq, and even if we eradicated I.S.I.S., we should expect it to metastasize. Meanwhile, the drain on the nation’s lives and budget would be immense.

When the Soviet Union collapsed in 1991, Western triumphalists claimed that there henceforth would be no alternative to global capitalism with a veneer of liberal democracy. But our destruction of a secular — if highly imperfect — alternative (namely, Communism and even socialism) left few outlets other than religious extremism. As global climate change and economic globalization put great strains on people, we can expect more violent challenges, unless we make space for truly democratic alternatives to the current economic and military world order.