After weeks of military buildup on Ukraine’s border—including deployment of 100,000 troops, repositioning dozens of attack aircraft and moving warships from the Caspian Sea to the Black Sea—Russian strongman Vladimir Putin appears to be pulling back from yet another invasion of Ukraine. “Appears” is the operative word here. Putin can easily and rapidly muster his troops for another snap exercise—setting the stage for another crisis, another bout of brinkmanship, another invasion, another war against democratic Ukraine. Whether Putin is muscle-flexing to intimidate Ukraine, to take the measure of President Joe Biden or to test NATO’s reflexes, Washington must prepare for—and seek to prevent—the worst: Putin’s seizure of more Ukrainian soil. Two of Biden’s predecessors offer a playbook for defending Ukraine’s democracy and confronting Putin’s aggression.

Eleven months before the attack on Pearl Harbor, as democracies fell and dictatorships surged around the world, President Franklin Roosevelt delivered what’s commonly called the “Four Freedoms” speech. He asked Americans to “look forward to a world founded upon four essential human freedoms…freedom of speech and expression—everywhere in the world…freedom of every person to worship God in his own way—everywhere in the world…freedom from want…freedom from fear.” What’s striking about FDR’s “Four Freedoms” speech—and relevant here—is that the main focus of the speech was his description of “unprecedented” threats to “American security.” Put another way, FDR understood that America’s interests and ideals were self-reinforcing—that defending and supporting the ideal of freedom “over there” serves American interests.

Thus, FDR called for “armed defense of democratic existence,” which would be premised on “putting forth our energies, our resources and our organizing powers” to provide fellow democracies “the strength to regain and maintain a free world.”

In a strikingly similar way, President Ronald Reagan pledged “to those neighbors and allies who share our freedom, we will strengthen our historic ties and assure them of our support and firm commitment.” Translating rhetoric into policy, Reagan signed National Security Decision Directive 75, which declared that America would “rebuild the credibility of its commitment to resist Soviet encroachment on U.S. interests and those of its allies,” support “Third World states that are willing to resist Soviet pressures,” and “contain and over time reverse Soviet expansionism.” In various ways and to varying degrees—technological assistance, covert support, weapons shipments, direct U.S. military intervention—what came to be known as the Reagan Doctrine bolstered anti-communist forces and democratic movements in Central America, the Caribbean, Poland, Africa and Afghanistan.

ASCF is proud to have played a role in Reagan’s efforts to turn rhetoric into policy. In fact, Reagan praisedASCF for encouraging the formation of the Coalition for Peace through Strength Caucus in Congress, for our efforts to promote deterrent military strength and for building a nationwide partnership of civic groups committed to this critical policy. With backing in Congress and at the grassroots level, Reagan was able to rebuild America’s deterrent military strength, and the Cold War with Moscow turned decisively in favor of the forces of freedom.

The Roosevelt-Reagan playbook has obvious applications for Ukraine in 2021.

For starters, we must remind the enemies of freedom—and perhaps ourselves—that resisting aggression and deterring aggression do not constitute aggression. “Such aid is not an act of war,” FDR matter-of-factly noted, “even if a dictator should unilaterally proclaim it so to be.”

So, when the Trump administration sent Javelin antitank missiles, cyber-defense systems, border-sensor capabilities and radar systems to Ukraine, that was a just and reasonable reaction to Russian aggression. Likewise, when the Biden administration approved an arms package for Ukraine that includes patrol boats, counter-artillery radars, satellite imagery and analysis capabilities, and medical treatment capabilities, that was a just and reasonable reaction to Russian aggression.

However, when the Biden administration canceled a planned deployment of Navy destroyers into the Black Sea—even as Russia was building up air, naval and land assets in the region—that sent the worst signal, at the worst time. Likewise, when the Obama administration delivered Ukraine “nonlethal aid” after the fledgling democracy was mugged by Putin in 2014, that only whetted Putin’s appetite, left democratic Ukraine exposed to Russian coercion, and erased any price Putin would have to pay for aggression. As Petro Poroshenko, then-president of Ukraine, said in late 2014: “One cannot win the war with blankets.”

To build on Poroshenko’s point, nor can aggression be deterred with blankets, MREs and the like. But it can be deterred with weapons. As DefenseNews reports, Ukrainian military commanders point out that when their troops “began using U.S.-provided Javelin anti-tank weapons, Russian tanks and armored personnel carriers that once operated with devastating impunity…backed off.” Col. Andrii Ordynovych, Ukraine’s military attaché in Washington, sees this as evidence of “strategic deterrence.”

Ukrainian officials are now seeking air-defense and anti-missile systems, such as Patriot batteries. More anti-tank missiles would make sense. Counter-artillery batteries and additional sensor systems will add sting to Ukraine’s arsenal.

The bottom line is that Putin must understand that there will be costs to his actions—and that the costs of further aggression will be greater than any potential benefits. That is the essence of deterrence, and it works.

To be sure, deploying more deterrent assets is important for Ukraine’s future as a sovereign, independent, democratic country. But it’s also important and relevant beyond Ukraine. With the backdrop of Ukraine—which he calls “Novorossiya,” a czarist-era term for Ukraine’s Russian-speaking regions—Putin warned in 2014 that he “will continue to actively defend the rights of Russians, our compatriots abroad, using the entire range of available means.” Given that there are millions of ethnic Russians in Eastern Europe—and that Putin has reserved for himself the right to determine when, where and whether they need to be defended—this is a recipe for something far more complicated than a new cold war. And this is precisely why the costs of invading and occupying Ukraine have to be raised—lest Putin be tempted to continue his salami-slice reincorporation of former Soviet lands.

However, those costs need not be limited to Ukraine. Washington has many cards to play beyond Ukraine—cards that can put Putin on his heels and even punish him. For example, Putin is remilitarizing the Arctic. In response, NATO should stand up an Allied Command-Arctic.

The groundwork is in place: Denmark has an Arctic command, Canada an Arctic training center, Norway an Arctic headquarters. The Pentagon has unveiled an Arctic strategy. It’s time for these NATO allies to coordinate their efforts, defend NATO’s Arctic interests, and force Putin to expend resources to counter NATO or to back down.

In addition, Putin is obsessed and deeply bothered by NATO enlargement. Not only can he do nothing to stop it; he realizes that it represents the consolidation and expansion of liberal democracy—and an ironclad check on his dreams of reconstituting the sphere of influence Moscow enjoyed during the Cold War. Thus, NATO should keep growing. The alliance added North Macedonia, Montenegro, Albania and Croatia the past decade—all despite Russian objections and Russian political interference. There’s momentum in Sweden for NATO membership. Finland routinely contributes to NATO exercises. Bosnia is participating in NATO’s Membership Action Plan, a pathway to full membership. Georgia and Ukraine are eager to be invited into the MAP program. Washington should encourage these developments and build diplomatic support for NATO’s next growth spurt.

In short, there are many pathways to helping democratic partners, defending the free world and punishing Putin.