At their summit in Vilnius, Lithuania, this week, the majority of the members of NATO wanted to offer Ukraine an invitation to join the alliance of democracies. This invitation was blocked by the U.S. because President Joe Biden believes that Ukraine is not “ready for membership in NATO.” Biden’s decision to block a timely invitation to Ukraine is wrong. It is dividing the alliance, endangering Ukraine, and sending a dangerous signal to Russian President Vladimir Putin.

Ukraine has formally applied to join NATO and has even written it into its constitution. Just a few days ago, President Volodymyr Zelensky told CNN that receiving an invitation during the NATO summit was crucial to his people. “The U.S. decide today whether Ukraine will get invited to NATO. … But this signal is really very important, and depends on Biden’s decision.”

France and the majority of our NATO allies supported making the membership invitation to Ukraine at the Vilnius summit in order to deter further Russian aggression against one of Europe’s largest democracies. This invitation would be the first step toward membership, but not the last. It usually takes countries at least a year to complete the membership process and often takes multiple years. This provides time for the conflict phase to be ended and a just and lasting peace to be negotiated.

The timing is critical. Russian forces are in retreat in Ukraine and Putin is focused on his internal opposition. Issuing the membership invitation to Ukraine now would end Putin’s ambitions for conquest and provide the biggest lift to the spirits of the Ukrainian people since their president said, “I need ammunition, not a ride.”

But the Biden administration appears determined to miss this valuable window of opportunity because of concerns about Putin’s reaction. Biden and most of his team believe they are being cautious and prudent to block Ukraine’s membership invitation. There is ample evidence that they are wrong to place their hopes on Putin’s reasonableness as a statesman, instead of on the courage and love of freedom of the Ukrainian people.

Let us separate facts from false hopes. Appeasing Putin does not work. After NATO deferred to Putin at the 2008 NATO Summit in Bucharest, Russia launched three invasions (Georgia in 2008, and Ukraine in 2014 and 2022) against its neighbors. The hopes that respecting Russia’s illegitimate sphere of influence would soften Moscow and keep the peace in Europe all failed. Repeating these mistakes and keeping Ukraine out of NATO due to fear of Russian behavior is foolish and dangerous.

Another key fact to remember is that Putin’s Russia and the mighty Soviet Union before it have attacked zero members of NATO. Moscow may hate NATO, but for 74 years the Russians have respected the collective defense of the transatlantic alliance and never attacked a NATO member. Moscow has complained or made threats many times, such as when the alliance was created in 1949, when Germany was unified from 1989 to 1991, and almost all of the 15 times since the Cold War that NATO has accepted a new member. What Russia has never done is escalate its complaints and threats into a military attack on a NATO member.

Thus, history shows a clear contrast between the two policy options being debated between NATO leaders and within the Biden administration. Trying to accommodate Russia and keeping willing European democracies out of NATO has resulted in war three times. Accepting democracies seeking NATO membership worked every time. NATO membership has deterred Russia and kept the peace in Europe.

It is not too late. Allies have proposed issuing the invitation to Ukraine at the next meeting of NATO foreign ministers in November. There is still time for Biden to realize the dangers of keeping Ukraine in Europe’s gray zone indefinitely. He can still make the urgently needed decision to invite Ukraine to become a member of NATO — not in some hypothetical future but this year.

Over the seven decades NATO has existed, the U.S. has many times come of out its comfort zone and taken responsible risks to protect democracy in Europe. Biden must not continue to promise Ukraine NATO membership “someday.” He should make the right choice and lead the U.S. and NATO to offer a membership invitation to Ukraine this year.

Jorge Benitez, Ph.D., is a non-resident senior fellow at the Scowcroft Center for Strategy and Security of the Atlantic Council and can be followed online @NATOSource.