European countries have accused Russia of repeatedly carrying out “hybrid” or “gray zone” attacks, which can include jamming communication systems, cyberattacks, sabotage, arson, the cutting of undersea cables, and more moves that don’t rise to the level of direct kinetic military action.

These gray zone operations have largely targeted countries along NATO’s eastern flank, closest to Russia’s borders. In recent months, these operations have appeared to come more frequently and more brazenly.

The Harvard report concludes that Russian President Vladimir Putin’s “core strategic objective is to fracture the NATO alliance,” and that it will likely continue their gray zone campaign against Eastern European countries “culminating in a limited military incursion into NATO’s northeastern flank.”

Since last September, Russian drones have entered Polish and Romanian airspace, three Russian MiG-31 fighter jets violated Estonian airspace, a Russian jet flew over a German Navy frigate in the Baltic Sea, and airports in Denmark and Norway had to shut down temporarily due to unknown drone activity.

There is currently an “unprecedented volume and frequency of potentially lethal attacks,” Laura Cooper, who served as the deputy assistant secretary of defense for Russia, Ukraine, and Eurasia during the Biden administration, said in December.

A possible option the Harvard paper identified would be for Russia to target a symbolic area near Russia or Moscow-friendly Belarus, such as the Estonian city of Narva, which is along Estonia’s border with Russia in the northeastern corner of the Baltic nation.

The Estonian Foreign Intelligence Service released its 2026 threat report on Tuesday, in which a foreword from Director General Kaupo Rosin states: “In the Estonian Foreign Intelligence Service’s assessment, Russia has no intention of militarily attacking Estonia or any other NATO member state in the coming year.”

One of the Estonian intelligence report’s top takeaways, however, is that “Russia’s immediate and more ambitious aims both serve to expand its influence and marginalize the United States and the West more broadly. In the economic sphere, Russia eagerly offers nominal cooperation and hopes to benefit in two ways: first, by binding U.S. and Russian interests more closely together; second, by widening what Moscow perceives as existing rifts between the US and Europe.”

If Russia were to launch a more aggressive military operation, which the Harvard report said is less likely, it could try to seize the Suwalki Gap, the tiny shared border between Poland and Lithuania, which also divides Kaliningrad and Belarus. If Russia were to militarily take this territory, it would separate Poland from the Baltics, which would pose challenges for the NATO alliance.

“The goal, then, is if you literally cut off Poland from Lithuania through the [Suwalki] Gap right there, you’re forcing NATO to resupply and deploy troops to the Baltics in a way that is very, very difficult,” Eric Rosenbach, one of the authors of the Harvard paper, told the Washington Examiner. “If right now, the main way that you’re going to resupply is via highway and rail links, you know, between Poland and Lithuania, and you cut that off, it will pose problems for NATO.”

Rosenbach said how Trump reacts to any Russian incursions will be “the major variable.” He has previously threatened to refuse to come to the aid of any NATO country that is attacked if it does not meet the defense spending minimum requirement. With Trump set to serve for another three years, this is a window in which America’s reliability toward the rest of NATO may be at a lower point than under nearly any other president since the alliance’s founding 76 years ago, and it could pose a “unique window of opportunity to fracture NATO’s security architecture,” the Harvard paper said.

Simultaneously, Trump’s push for Europe to take its security into its own hands could also help NATO members be more prepared if a military attack were to occur.

The Trump administration is trying to secure an end to Russia’s war in Ukraine, which is nearing the four-year anniversary of Putin’s full-scale invasion. The Russian military has suffered more than one million casualties during that time frame, but only occupies about 20% of Ukraine in the eastern and southeastern parts of the country.

The U.S. recently held trilateral talks with both Russian and Ukrainian officials. Even though Russia is participating in the talks, it has demanded that Ukraine make significant concessions in any deal, such as giving up land Russia has not captured and imposing post-conflict limits on Ukraine’s military.

There is also a possibility that Russia and China could coordinate attacks against American interests, forcing the U.S. to decide how to divide resources against two major powers.

“Despite a certain level of mutual distrust, both China and Russia recognize that, for the foreseeable future, they will benefit more from maintaining good relations with one another than from pursuing potential agreements with the U.S. administration,” the Estonian report said.

US-RUSSIA NUCLEAR TREATY TO EXPIRE AS ATTENTION TURNS TO CHINA’S EXPANDING ARSENAL

The two countries have become closer allies in recent years, largely since Russia’s full-scale invasion of Ukraine in 2022, as Western sanctions forced Moscow to look elsewhere for support.

A Russian attack on NATO coordinated with a Chinese attack on Taiwan could be “within the vital interests of both of those countries in a way that makes them more likely,” Rosenbach, who served as the chief of staff to the Secretary of Defense from 2015 to 2017, added.