Vilnius is the capital of Lithuania, a vibrant country of 2.8 million people just south of Latvia and north of Poland, along the Baltic Sea. Its rich 800-plus-year history is marked by conquest and subjugation, prosperity and poverty. Moscow, a day’s drive to the east, seems to be the recurring threat throughout its existence. Indeed, this young democracy shed the yoke of Soviet occupation just a mere 33 years ago. 

For many, the Cold War is a vivid and terrible memory that has been triggered by Vladimir Putin’s brutal invasion of Ukraine. It is said that history doesn’t repeat. Yet one can’t help but see the Russian war crimes in Ukraine — murder, torture, rape, and deportations on a mass scale, for example — as the same atrocities Moscow committed against Lithuania and others from World War II onward. Just tour the notorious KGB building-turned-museum in downtown Vilnius that chronicles this awful tale over five decades to see how painfully obvious it is. 

Not surprisingly, this tragic past guides Lithuanian strategic thinking and actions today. It is why they are meeting their NATO funding commitments, contributing more than their fair share of military assistance to Kyiv, and even hosting Ukrainian families in their homes. Their example is prodding others to do the same.   

Last week, in this proud city, I keynoted the annual Baltic Military Conference, a gathering of national security experts and officials of all stripes where the major issues facing NATO are debated. The war in Ukraine was naturally the main topic of discussion, but the question on everyone’s mind was whether Washington would continue to support Kyiv.

My answer often elicited a combination of relief and concern. Yes, I said, I believe the U.S. will continue its support, even though polling indicates slippage among the American people. To arrest this, I added, it is important that our nation’s political leaders, beginning with President Biden, clearly and often state our goals, our strategy, and our reasons for acting. Moreover, they must do so in terms that are simple, straightforward, and compelling. We have not heard this yet, unfortunately. 

And while there are soft spots in both political parties for aiding Ukraine, we Republicans have the additional burden of explaining to our larger "America First" crowd that U.S. security is strengthened when we have good allies and partners, when we help them defend themselves from autocrats who threaten our shared values and interests, and that standing up to a dictator in Moscow sends the right message to (and helps deter) the other, more challenging one in Beijing. 

But I also told my European friends that they must do more. We need our NATO allies to start meeting a commitment they made in 2014 to spend two percent of GDP on defense. Only nine out of 30 members are currently doing so. Fact is, this should be a floor that all our Western allies achieve.

Additionally, most countries need to ramp up their military support to Ukraine. The U.S. and a few others cannot bear most of this burden. It only erodes public support here at home when Americans believe we’re carrying the bulk of the load. I suspect this sentiment, coupled with a skyrocketing national debt, helped birth the "no blank check" statement by the speaker of the House. Regardless, demanding scrutiny and accountability for U.S. assistance, as I interpreted this remark, is not unreasonable. 

If these things happen, then I’m confident that U.S. support to Ukraine will indeed continue, and that American leadership and credibility — so vital in the complex and dangerous world we face today — will be sustained. Both are critical to success in this first major fight of the 21st century between autocracy and democracy. 

In July, Vilnius will host the annual NATO summit. It will be a historic gathering that, among other things, should see: two more countries — Sweden and Finland — join the alliance; an agreement by member states to commit more of their GDP to defense; an affirmation that NATO’s door remains open, especially for Ukraine and Georgia; and finally, a celebration of a successful Ukrainian offensive that made great progress in pushing Russian forces back to their own borders. 

Such accomplishments would not only invigorate NATO and diminish Moscow, but would also give all allies greater cause to continue assisting Kyiv while delivering a major blow to Putin’s strategy of outlasting Western resolve. It would also be a fitting tribute to do this all in Lithuania, a sturdy ally that has punched above its weight and pushed back against Russian aggression for hundreds of years.

Dr. Mark T. Esper was the 27th secretary of Defense and 23rd secretary of the Army, and author of the NYT bestselling memoir "A Sacred Oath: Memoirs Of A Secretary Of Defense During Extraordinary Times."