Western allies fear that Russia will gain sovereignty over Belarus, a former Soviet satellite state that could help preserve Vladimir Putin’s grip on power and sharpen Kremlin threats against NATO members.

Russian expansion is on the table because Putin is trying to finalize the implementation of a union treaty that the two countries signed in 1998. Moscow and Minsk interpret the agreement differently, but Putin has begun to apply economic pressure to Belarus while scheduling a flurry of meetings with Belarusian President Alexander Lukashenko over the last year.

“I think this mild annexation will just happen, probably next year,” Alisa Muzergues, a foreign policy analyst at GLOBSEC in the Slovak Republic, told the Washington Examiner. “To be honest, my personal feeling is that it's already a done deal."

Such a maneuver could end Lukashenko’s tenure as “the last dictator in Europe,” while providing Putin with a political life-preserver. Currently, presidential term limit laws require him to leave the Kremlin in 2024. A union with Belarus would allow him to circumvent those limits and continue to rule the revised Russian state, pending a new election he is expected to win.

The prospective agreement is widely regarded as a way to provide a new legal basis for Putin to remain in power, sources told the Washington Examiner. The stakes for Putin are high.

“The Kremlin is not monolithic, there are many factions,”a Baltic official told the Washington Examiner. “Right now, Putin is the force which keeps them from cutting each other's throats, but if he leaves power he understands that he himself becomes vulnerable.”

The prospect of a Russian expansion has caused open anxiety among NATO allies, including in Lithuania, a Baltic Sea neighbor that joined the transatlantic alliance in 2004.

“During the last year, Russia’s pressure towards Belarus to implement the obligations under the Agreement on Establishment of the Union State of Belarus and Russia increased,” Lithuania’s Foreign Ministry told the Washington Examiner, referring to an ambiguous union agreement that the two sides signed in 1998. “It is a sovereign choice of Belarus with whom and how to integrate. However, independent, sovereign Belarus is our national interest.”

Lukashenko has balked at what he calls Putin’s demand that he “bury the sovereignty and independence” of Belarus. He has avoided signing an agreement, but the two leaders have met twice in the first three weeks of December.

"Overall, since the Soviet Union collapse we have not drifted apart too much from each other,” Lukashenko said following a Friday meeting with Putin in St. Petersburg. “Even though we did not enact the points envisaged there, we did not stray away from each other either as it happened with Russia and other republics in the post-Soviet space and not only the Baltic states or Ukraine.”

Hundreds of activists risked the wrath of Lukashenko’s security services to protest against integration with Russia during both of his meetings with Putin, including a Friday gathering of 1,500 people who warned that “Union with Russia means War and Poverty.” An unknown street artist lampooned the meeting with graffiti of Putin and Lukashenko kissing, to the delight of Belarusian nationalists.

“Lukashenko signed most of the agreements with Putin,” Franak Viačorka, a prominent local journalist, tweeted. “It seems 2020 will be the critical year for Belarus' future and independence. And these protests are not the last.”

Lithuania’s acknowledgement that Vilnius is “closely monitoring” the possibility that Russia will absorb Belarus reflects the concern that a merger would fortify Putin’s political and military power within quick striking distance of a vulnerable part of the NATO alliance.

“Baltic states are in between Kaliningrad and Belarus, and that also is probably the weakest link in NATO,” the Baltic official said. “Belarus is very far to the west, so Russians can use it to project power.”

Kaliningrad is a Russian exclave that Moscow has controlled since the Cold War, even though the territory does not connect by land to Russia. The district, stocked with Russian military assets, is surrounded by Poland and Lithuania, but the Polish-Lithuanian border creates only a small buffer of NATO territory between Kaliningrad and Belarus.

“In that 50 miles, they're cutting off the three Baltic states from the territory of NATO,” the Baltic official said, while discussing the possibility that Putin might try to connect Belarus with Kalinigrad.

That fear is unlikely to become a reality as long as NATO forces, such as the small contingent of U.S. soldiers currently deployed to Lithuania, remain on the ground, the source added. Belarus has no such protection, though U.S. officials are trying to provide indirect political help. Then-White House National Security Advisor John Bolton traveled to Minsk to meet Lukashenko in August. State Department officials, for their part, are encouraging Belarusian independence by meeting with local activists.

“They are kind of on the front lines,” Robert Destro, who leads the State Department's democracy and human rights bureau, told reporters last week. “They get . . . that in order to really stave off the embrace of the Russian bear that they have to develop their own civil societies. I mean, what does it mean to be a Belarusian?”

That’s difficult, observers say, because Lukashenko’s autocracy has repressed Belarusian activists, while allowing Putin to expand Russian influence in the country.

“It's a bit too little too late, to be honest with you, because the country is completely dependent on Russia,” Muzergues, the GLOBSEC analyst, said. “If something were to happen [like what's] happening in Ukraine, I'm not sure the population would resist it.”

Still, some observers hold out hope that the authorities in Minsk can thwart Putin’s ambitions.

“It's worrisome to see the increased pressure and slight urgency from Russia to get this union state,” the Baltic official said. “But, on the other hand, Lukashenko is in power longer than Putin. And, that is a sign in itself.”