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Perhaps inevitably, the 2024 presidential campaign is quickly becoming a clash of first principles, one that will require repeating basic facts about the world and repudiating lies.

Here's one such fact: The North Atlantic Treaty Organization (NATO) is among the most successful military alliances in history, securing peace and prosperity across the Western world for nearly 75 years. Destroying it for no reason would be a bad idea.

It's regrettable that this reality needs to be defended — and will surely remain a point of contention across the next nine months of campaigning — but so it goes. Donald Trump's recent suggestion that he'd "encourage" Russia to attack NATO countries that fall short of their defense-spending commitments demands to be called out.

By openly casting doubt on America's commitments to its allies, the former president has already damaged the U.S.'s standing. Even more dangerous is that this line could harden into actual policy in the unfortunate event that he succeeds in getting reelected.

As voters ponder their choices in this election, it's crucial that they reflect on just how wrong Trump is.

The first and most essential point is that NATO serves vital U.S. interests as well as those of its friends — something that Trump implicitly denies. The alliance cements U.S. global leadership, which hugely benefits Americans, and not only in matters of security. As the preeminent global power, the U.S. faces numerous actual and potential adversaries, states and nonstate actors alike.

Collaborating with allies expands its political influence, boosts trading ties and — through intensive force alignment, intelligence sharing and joint military operations — strengthens the country's ability to respond to transnational threats. Consider NATO's collective response to the Sept. 11 attacks, its counterterrorism operations in Africa and the Middle East, and more recent efforts to defend against cyberattacks. The U.S. is strong, but not so strong that it doesn't need friends.

It's true that NATO was first conceived as an alliance to defend Western Europe against the Soviet Union. That purpose — with Russia again intent on regional domination — remains vital. In turn, this obliges Europe's governments to play their full part and keep their promises on defense spending. Their failure to fully honor their obligations is a long-running scandal, and Washington should indeed press all NATO members to spend the promised 2% of gross domestic product on defense. In the wake of Vladimir Putin's war on Ukraine, they've lately been ramping up their spending.

But let's be clear. Tough negotiating with allies over sharing costs is one thing. Threatening to abrogate the treaty if its members don't instantly submit to U.S. demands — going so far as to say that the U.S. would have no objection to Russian aggression — gravely weakens the alliance's credibility. The importance of maintaining this asset is hard to overstate.

As Putin and other adversaries make their calculations about what they can get away with, America's perceived willingness to stand with its allies is paramount. If the U.S. is seen to be wavering on its commitments, or even eager to walk away from them, its adversaries will surely be emboldened. In short order, that will leave the U.S., at home and abroad, weaker and in greater peril.

Angry responses to Trump's reckless declarations often serve his purposes. Sometimes, as in this case, they're necessary anyway. Trump is once again telling voters that he's unfit for the presidency. They should listen.