The first stop on the road that led to the current crisis in Ukraine was Kabul. The way that President Joe Biden left Afghanistan was a stain on America’s honor and prestige, and has invited U.S. adversaries, particularly Russia, to test the White House.

Over the past several weeks, Russia has been conducting a sizeable military buildup along its border with Ukraine, in Belarus, and in occupied Crimea. There are almost 100,000 troops now positioned on Ukraine’s borders with more arriving every day. In addition, Russia has deployed a robust naval presence in the Black Sea the size of which is unprecedented in modern times. Russia’s plan is unclear, but one thing is certain: If Moscow wants to further invade Ukraine, it now has the ability to do so.

During this sensitive time, the United States should immediately show its solidarity with Ukraine. The U.S. should also rally North Atlantic Treaty Organization (NATO) members to show solidarity with Ukraine and increase the defenses of the Alliance, bolster Ukraine’s defensive military capabilities by rushing weapons and other supplies to Kyiv, and ensure that Ukraine remains on the path to NATO membership. Finally, and crucially, the White House must urge Ukrainians to fight for their country, contrary to what the Obama Administration did in 2014 when Russia first invaded.

Russian Aggression

At every turn since coming to power in 1999, Russian President Vladimir Putin has sought to undermine U.S. interests. Whether this has been through invasion of U.S. partners, use of banned chemical weapons to assassinate dissidents in the United Kingdom, sophisticated cyberattacks against Americans, or election meddling and spreading disinformation, Putin has demonstrated that he cannot be trusted. An easy Russian takeover of Ukraine will embolden Putin to be even more aggressive in the future. The loss of human life and the economic impact of a major war in Eastern Europe are impossible to calculate.

In 2014, Russia invaded Ukraine. Since then, Russia has illegally occupied Crimea, which includes approximately 7 percent of Ukraine’s landmass and more than half of its coastline. Russia provoked and now supports a separatist movement in eastern Ukraine that did not previously exist. Russia continues to propagate a war that has resulted in more than 13,000 lives lost and 30,000 wounded, heavily damaging the Ukrainian economy and hampering Ukraine’s progress toward deepening ties with the West.

Russia is the aggressor, and Ukraine is the victim. For Americans who believe in strong and secure national borders, the primacy of national sovereignty, and the right to self-defense, support for Ukraine in the face of Russian aggression is natural.

Modern Ukraine represents the idea that each country has the sovereign ability to determine its own path, to decide with whom it has relations, and how, and by whom, it is governed. No outside actor (in this case Russia) should have a veto on any country’s membership or closer relations with organizations, such as NATO. In many ways, the future viability of the transatlantic community will be decided in Ukraine.

What Will Russia Do? Six Scenarios

While it is impossible to predict what Putin has planned, some general assumptions can be made based on what is known about the size and configuration of Russia’s military buildup and historical precedent of Moscow using military force to achieve geopolitical objectives. Some possibilities include:

1) The non-kinetic scenario. Russia uses the military buildup to try to extract concessions from the West on NATO enlargement. Russia’s strategic goal here is to keep Ukraine distanced from organizations like NATO and the European Union. Russia would also benefit from the long-term integration of Ukraine into Moscow-backed groups like the Collective Security Treaty Organization or the Eurasian Economic Union. The most effective way for Russia to achieve this goal is by keeping the conflict in eastern Ukraine “frozen”—meaning that the major fighting stops, but localized fighting remains without a conclusive end to the conflict. That means using the troops on the border as political leverage not as actual aggressors. Considering the size of the Russian force currently mobilized, this scenario looks less likely.

2) A limited offensive to entrench Russian-backed separatists. A plausible scenario, assuming a lack of U.S. and European resolve, is that Moscow helps the separatists to consolidate gains in the Donetsk and Luhansk regions to create a political entity that functions more like a viable state. This could involve the capture of major communication and transit nodes (such as the city and port of Mariupol) and the Luhansk power plant, all of which are under Ukrainian government control. While this could be done in a piecemeal manner, such a move would also require the complete abandonment of any notion of a cease-fire.

3) More aggressive push for a land bridge to Crimea. Currently, the Russian Federation is connected to Crimea only by a newly built bridge across the Kerch Strait. Ukraine has also blocked Crimea’s main source of fresh water. Connecting Russia to Crimea along the coast would alleviate some of Russia’s logistical challenges, especially as it pertains to fresh water, while turning the Sea of Azov into a Russian lake. However, this would require a sizeable military force breaking through strongly fortified positions along the frontlines of the Donbas and the capture of Mariupol, Ukraine’s 10th-largest city.

4) Large offensive to capture major cities. One of the most aggressive scenarios could involve Moscow’s attempt at re-establishing control of the Novorossiya region of imperial times in southern Ukraine. This would create a land bridge between Russia and Crimea, eventually linking up with the Russian-occupied Transnistria region of Moldova. This would require a large-scale mobilization of Russian forces sufficient to take over Odessa (Ukraine’s third-largest city) as well as Mariupol. If successful, this would fundamentally change the geopolitical and security landscape in Eastern Europe in a way not seen since World War II.

5) The “raid on Kyiv.” Russia could use its massive military force to punch through Ukrainian defenses and make a dash to the capital city Kyiv. In this scenario, Russian troops would take punitive measures against the Ukrainian military while stopping outside the capital—only to then “voluntarily withdraw” to a pre-determined position after the international outcry. By getting close to Kyiv, the raid scenario allows Russia to send a message to Ukraine that it could take the capital without devoting the resources and manpower that would be required to do so. Second, a “voluntary” withdraw would create a (false) perception that President Putin is the one de-escalating the conflict.

6) A wildcard. Russia stirs political problems in Ukraine’s Budjak region in the Odessa Oblast. The main goal here would be to manufacture a local political crisis that causes problems for the central government in Kyiv. Moscow attempted a manufactured political crisis a few years ago.REF Budjak is only connected to the rest of Ukraine by one regional road. Bordering Budjak is Moldova’s autonomous Gagauzia region. This ethnically Turkic, Orthodox Christian, and Russian-speaking region has close links to Moscow and is pro-Russian. Domination of Budjak, in addition to Russia’s military presence in Transnistria, would put Moscow in control of a sizeable stretch of Ukraine’s western border—which would also threaten the stability of Odessa.

Any scenario involving conventional military operations would also include sophisticated cyberattacks, effective disinformation campaigns to undermine local and international support for Ukraine’s government, and the activation of “little green men” and other political antagonists to subvert local and national government institutions as was done in Crimea in 2014.

Ukrainians Will Fight

Since Ukraine is not a member of NATO, the U.S. does not have an obligation to deploy combat troops to defend the country. And, the Ukrainian government is not making such a request. Ukrainians are more than willing and capable to fight for themselves. Thanks to the support and training from the United States, the United Kingdom, Turkey, Poland, and the three Baltic states, the Ukrainian armed forces have never been better trained, equipped, experienced, and motivated.

NATO continues to have an interest in helping Ukraine to defend itself. Russia’s continuing aggression undermines transatlantic stability. There are prudent measures that the U.S. can take to support Ukraine short of deploying American combat troops into the country. The U.S. should:

• Urge Ukrainians to fight and support them with weapons and intelligence. This is the single most important thing that the Biden Administration can do. In 2014, when Russia first invaded, the Obama Administration told Ukrainians not to fight and to instead wait for a diplomatic process to resolve the crisis. Eight years later, diplomacy has failed. If the U.S. was invaded, Americans would fight. The same should be expected of Ukrainians.
• Supply more weapons to Ukraine—immediately and without restrictions. Every country has the right to self-defense. Weapons can be an effective part of a larger strategy for assisting Ukraine. As authorized by successive National Defense Authorization Acts, the U.S. should rapidly send weapons and supplies to Ukraine, including more anti-armor weapons, anti-aircraft weapons, and small arms with no restrictions.
• Implement devastating top-to-bottom economic sanctions against the Russian Federation. A further military intervention in Ukraine should trigger devastating economic sanctions targeting not only the Kremlin’s political elites and oligarchs but also the Russian banking and financial sectors and key industrial sectors. However, economic sanctions are not an answer by themselves, and must be a part of a larger strategy to deter Russia.
• Kill Nord Stream 2 right now—not after Russian military action. Nord Stream 2 is a Russian gas pipeline that will connect Russia directly to Germany through the Baltic Sea. Russia prefers this method because it removes Ukraine from the transit route and makes Europeans more dependent on Russian gas. Nord Stream 2 is neither economically necessary, nor geopolitically prudent. The Biden Administration should use every tool available to ensure that Nord Stream 2 is never used. Also, the Administration should double down on supporting an expanded Southern Gas Corridor connecting Caspian gas to southern Europe, encouraging the construction of a Trans-Caspian Pipeline to bring natural gas from Central Asia to Europe bypassing Russia, and bolstering the Three Seas Initiative to improve energy connectivity in Eastern Europe.
• Bolster the defense of NATO’s eastern flank. If major fighting breaks out in Ukraine, there is a real possibility that the conflict will spread to neighboring countries. The U.S. has a treaty obligation under NATO to help to defend the territory of the Alliance’s members. The U.S. should take prudent and responsible measures to ensure that the required force posture is present in Europe to deter, and if necessary, defeat, Russian aggression against a NATO member.
• Assess the impact of potential Ukrainian refugees in Eastern Europe. If Russia does end up intervening militarily again in Ukraine, many civilians could become internally displaced persons (IDPs) or refugees. Destabilizing in normal times, dealing with large numbers of refugees during the COVID-19 pandemic would be even worse. The U.S. should discuss with these nations the potential impact this could have on their infrastructures and security, and how to best plan for this possibility before it becomes a reality.

U.S. Leadership Is Essential

It is in America’s interest that Ukraine remain independent and sovereign and maintain the ability to choose its own destiny without outside interference. While the success of Ukraine will rest in large part on the shoulders of Ukrainians themselves, U.S. leadership is essential for counteracting Russian aggression and supporting Ukraine. The U.S. should seize the opportunity to move quickly and robustly to reaffirm American commitment and support to the people of Ukraine. In turn, both America and its allies will be safer.

Luke Coffey is Director of the Douglas and Sarah Allison Center for Foreign Policy, of the Kathryn and Shelby Cullom Davis Center for National Security and Foreign Policy, at The Heritage Foundation.