September 27, 2026: As the Russian war in Ukraine enters its fifth year, NATO intelligence sources are increasingly warning that Russia also poses a growing threat to countries in the Baltic region. So far, the confrontation has produced only isolated incidents, such as drone incursions into these countries’ airspace. Latvia, Lithuania, Estonia, Poland, and Finland increasingly must decide how they would collectively defend themselves against a major Russian invasion. This is not a new threat. A century ago, the Baltic states attempted to form a military coalition for mutual defense against the Soviet and German threat. Such an alliance never came to pass, and the Baltics spent World War 2 under German control, followed by nearly half a century of Communist rule.

The security situation in the Baltic Sea has changed significantly since Russia’s full-scale invasion of Ukraine began. Finland and Sweden have joined NATO, while the Baltic states and Poland have accelerated their rearmament and efforts to strengthen the alliance’s eastern flank. Disputes within NATO over burden-sharing have also intensified: President Donald Trump’s administration is demanding that Europe rely more on its own resources and spend more on defense, while Europeans are increasingly debating whether they can still count on the same level of American involvement in the alliance.

Three years ago, the Baltic States, Estonia, Lithuania and Latvia, increased their defense spending and aimed for three percent of GDP on their armed forces. They also took a more dramatic step: severing economic ties with Russia. For 65 years, Estonia and the other Baltic States received their electrical power from Russia. In early 2025, the Baltic States switched to the European electricity network. This left the Russian Baltic Sea enclave of Kaliningrad, formerly German Konigsberg, isolated from Russian power supplies. This enclave now depends on new coal- and gas-fired power plants with coal and liquid natural gas shipped in from Russia. The enclave also serves as a base for Russian retaliation against the Baltic States. This is in the form of Russian merchant ships dragging their anchors along the seafloor to break or damage electrical or communications cables. With Russian forces tied down in Ukraine, Baltic States military and police forces boarded the offending Russian ships and encouraged the crews to cease their mischief.

This dramatic switch from Russian to European energy sources included rearming with Western weapons. Estonia led the way by dramatically increasing orders for new military equipment. Estonia is spending $14.5 billion over a decade to build up munitions stockpiles and acquire modern weapons. These include Israeli Harpy loitering munitions and Spike Anti-Tank Guided Missiles/ATGMs, which are on order. Blue Spear land-based anti-ship missiles arrived in 2024. These have a range of 290 kilometers, and Estonia is launching them from trucks. These mobile missile launchers can be moved around, making them more difficult to hit with airstrikes. Estonia ordered 36 K9 self-propelled howitzers from South Korea, and all have been delivered. Six HIMARS vehicles and a large supply of the guided missiles these vehicles carry have arrived. Several hundred wheeled armored personnel carriers were purchased to replace the trucks many infantry units now use.

The currently recommended NATO goal is two percent of GDP for defense, but Estonia and the other Baltic states have exceeded that because of the Ukraine war. That means air defense systems were upgraded with new radars and fire control systems for new anti-aircraft missile systems. These include the Polish Piorun for low-flying threats and the German IRIS-T for more distant, higher-flying aircraft and missiles. Estonia increased the size of its active-duty armed forces from 26,000 to 36,000.

Estonia is a small country with a population of 1.3 million and a GDP of $44 billion. That means per-capita GDP is $46,000. Poland and the Baltic States made an extraordinary, financially costly effort to assist Ukraine during the first six weeks of the war. For example, tiny Estonia spent about 0.8 percent of its annual GDP to support Ukraine during those six weeks. Most of the aid went to processing and hosting Ukrainian refugees fleeing the Russian attacks on their homes. By late 2022, Ukrainians and their NATO supporters were planning for what comes after the war. By 2025, Russian troops were on the run, and Russia had few options left. Estonia is convinced that Russia will try again, and the next time Estonia might be the target.

This is not a new problem. Back in 2016, the Baltic States asked for some American troops. Not enough to halt a Russian invasion, just enough to ensure that the Americans and their NATO allies, or at least some of them, would intervene if Russia did attack. The Baltic States already have a mutual defense guarantee from NATO through NATO membership. But that is not enough, and what has been asked for, and granted, are some American troops in each of these nations. The response was to send one reinforced battalion to each Baltic State. Since the Russian invasion of Ukraine began in 2022, the Americans have put more personnel, most of them support troops, in Poland and the Baltic States.

The Baltic States and neighboring Poland join a growing list of nations that, threatened by dangerous neighbors, have agreed, and often been asked, to host American troops. The first and most obvious examples are South Korea, Japan, and Germany. A few nations in the Middle East have quietly followed this model, including Saudi Arabia, Kuwait, Bahrain, and the United Arab Emirates (UAE). All these Persian Gulf nations want the Americans around to keep the Iranians out. But it is not just the Iranians. Inside Iraq, there have been American troops in northern Iraq to protect the autonomous Kurdish majority up there from the Arab majority since the early 1990s. This form of security is also called a tripwire force because, if the host nation is attacked, the presence of some U.S. troops means that a lot of U.S. reinforcements will promptly arrive. Several other nations are seeking this form of security guarantee but are not getting it, at least not yet. This includes Ukraine and Georgia. The United States is the favored source of these armed hostages because the U.S. is a superpower and, compared to all the alternatives, the least likely to take advantage of the situation.