When someone is senile but surrounded by supporting friends and family, it’s a situation that is sad but, one hopes, manageable. When someone is senile but that someone is also the president of the United States, it’s downright dangerous. The whole world has now seen President Joe Biden’s undeniable senility.

To be clear, former President Donald Trump’s “mirror, mirror on the wall” school of foreign relations is very far from ideal. Trump does whatever he believes is in his own interest in any one moment. He is unable to separate his perception of his own interests from those of the nation. But at least for now, Biden occupies the Oval Office. And that makes the president’s catastrophic debate performance on Thursday a cause for deep concern regarding national security.