The White House description ofDonald Trump’s speech Thursday in Warsaw was simply, “Remarks by President Trump to the People of Poland.” In truth, Mr. Trump’s remarks were directed at the people of the world. Six months into his first term of office, Mr. Trump finally offered the core of what could become a governing philosophy. It is a determined and affirmative defense of the Western tradition.

To be sure, Mr. Trump’s speech also contained several pointed and welcome foreign-policy statements. He assured Poland it would not be held hostage to a single supplier of energy, meaning Russia. He exhorted Russia to stop destabilizing Ukraine “and elsewhere,” to stop supporting Syria and Iran and “instead join the community of responsible nations.” He explicitly committed to NATO’s Article 5 on mutual defense.