 was signed 75 years ago. The Biden administration has taken pride in strengthening and expanding NATO in the face of Russia's war in Ukraine. And Biden will be meeting with Ukraine's President Zelensky this week. But looming over this NATO summit are questions about the future of this unity, given the uncertainty around the U.S. presidential election. The presumptive Republican nominee, Donald Trump, has repeatedly raised questions about the U.S. commitment to the alliance.