President Donald Trump spoke to a massive crowd in Warsaw’s Krasinski Square on Thursday, pledging to defend Poland’s independence and Europe’s identity.

Trump’s affirmation of U.S. ties to the young democracies of Eastern Europe aims to restore relationships damaged by President Barack Obama, who spoke to the Czech people in Prague in 2009, only to turn his back on them — and on Poland — by abandoning missile defense later that year.

Notably, both presidents chose to make a clear commitment to Eastern Europe in their first year in office, against a growing threat from Russia that challenged both administrations. But Obama had chosen appeasement with the Russian “reset” and nearly everything else that followed, until the invasion of Crimea. Trump pledged better relations with Russia, but has adopted a more confrontational posture thus far, especially at the UN and in Syria.

It is important to remember just how profound President Obama’s betrayal was. He promised the people of Prague:

So let me be clear: Iran’s nuclear and ballistic missile activity poses a real threat, not just to the United States, but to Iran’s neighbors and our allies. The Czech Republic and Poland have been courageous in agreeing to host a defense against these missiles. As long as the threat from Iran persists, we will go forward with a missile defense system that is cost-effective and proven. (Applause.) If the Iranian threat is eliminated, we will have a stronger basis for security, and the driving force for missile defense construction in Europe will be removed. (Applause.)

Obama did exactly the reverse of what he said he would do: he abandoned missile defense in Europe long before he reached a deal with Iran. That decision set the stage for an Iran deal that was considerably weaker than promised.

Worse, Obama informed the Czech prime minister of his decision on missile defense after midnight, and told the Polish prime minister on September 17, 2009, which was the 70th anniversary of the Nazi invasion of Poland.

Trump sought to undo Obama’s actions, and to rebuild the U.S. alliance with Eastern Europe, by re-casting the relationship not just as one of military and economic benefit, but as one of shared values:

Speaking of the defenders of the Jerusalem Avenue crossing in the Warsaw uprising, Trump said:

Those heroes remind us that the West was saved with the blood of patriots, that each generation must rise up and play their part in its defense, and that every foot of ground, and every last inch of civilization is worth defending with your life. Our own fight for the West does not begin on the battlefield. It begins with our minds, our wills, and our souls. Today, the ties that unite our civilization are no less vital and demand no less defense than that bare shred of land on which the hope of Poland once totally rested. Our freedom, our civilization, and our survival, depend on these bonds of history, culture, and memory. And today as ever, Poland is in our heart, and its people are in that fight. Just as Poland could not be broken, I declare today, for the world to hear, that the West will never, ever be broken. Our values will prevail, our people will thrive, and our civilization will triumph.

Those are terms that Obama, speaking in Prague of an “interconnected” globe, nuclear disarmament, and aid to the “impoverished” people of the world, would have rejected emphatically. Ultimately, Obama could not deliver on his vague commitments, and broke his explicit promises, because he would not confront the shared enemies of the U.S. and Eastern Europe.

Trump’s vision acknowledges that there are parts of the world that reject and threaten the values of the West, and seeks to re-establish U.S. alliances on the basis of a shared commitment to prevail against them.

Joel B. Pollak is Senior Editor-at-Large at Breitbart News. He was named one of the “most influential” people in news media in 2016. He is the co-author of How Trump Won: The Inside Story of a Revolution, is available from Regnery. Follow him on Twitter at @joelpollak.