By Adam Ereli     February 24, 2016

Two days before Christmas, as American policymakers were settling into the holidays, Russia quietly signed a sweeping air defense agreement with Armenia, accelerating a growing Russian military buildup that has unfolded largely under the radar. It was the most tangible sign yet that Putin is creating a new satellite state on NATO’s border and threatening an indispensable U.S. ally.

The buildup in Armenia has been glossed over in Washington, despite being a key piece of Vladimir Putin’s plan to dominate the region — along with its proxy Syria and growing military ties with Iran. Most importantly, Armenia shares an approximately 165 mile border with Turkey, a NATO member and the alliance’s southern flank.

Over the last six months — as Russia’s war in Syria and pressure on Turkey has intensified — the flow of its arms and personnel into Armenia has escalated to include advanced Navodchik-2 and Takhion UAV drone aircrafts, Mi-24 helicopter gunships and Iskander-M ballistic missiles. Last July, Putin ordered snap combat readiness checks in Armenia to test the ability of his forces to react to threats to Russia’s interests abroad. Earlier this month on orders of Russian Defense Minister Sergei Shoygu, Russia began a massive military exercise in its “southwestern strategic direction,” which includes Armenia. The total strength of the regional operation included approximately 8,500 troops, 900 ground artillery pieces, 200 warplanes and 50 warships.

The growing Russian military presence in Armenia is but the latest indicator of a worrisome trend: Putin’s threat to NATO and America’s interests in Europe.

The Armenian-Russian alliance is gaining strength

The Armenian-Russian alliance is gaining strength. Armenia currently hosts an estimated 5,000 Russian military personnel and two Russian bases. In 2010, both countries signed an agreement that extended Russia’s basing rights in Armenia by 24 years, until 2044, and committed Moscow to supply the Armenian armed forces with “modern and compatible weaponry and special military hardware,” according to Armenian President Serzh Sargsyan. The 102nd Military Base in Gyumri, Armenia — nearly 120 kilometers from the capital (and less than 10 kilometers from the Turkish border) — has become a crucial Russian beachhead.

A similar Russian deployment on the borders of any other NATO member state would produce an outcry of outrage. Why are we staying silent in the face of this thinly veiled aggression against Turkey? And why are we not speaking up against Armenia for rolling out the red carpet for Putin’s shock troops?

Turkey, after all, is a critical ally in the global fight against ISIS and is among the only members of the U.S.-led coalition with bases near strategic ISIS strongholds. In July 2015, Turkey and the U.S. finalized an agreement to work cooperatively to combat Islamic State terrorists in Syria and Iraq, allowing the U.S. to launch air attacks from the Incirlik air base in southern Turkey against Islamic State terrorist networks in northern Syria.

In international diplomacy, geography is everything

We ignore this threat at our peril. And in international diplomacy, geography is everything. Armenia borders three critical U.S. allies: Georgia, Azerbaijan and Turkey. Russian forces currently occupy Georgian territory. Azerbaijan steadfastly resists intimidation from Moscow and is the linchpin in our efforts to wean Europe from dependence on Russian energy supplies.

Make no mistake: The Russian military presence in Armenia represents a dagger pointed at the heart of NATO as the Armenia-Russian alliance strengthens. But while Moscow is rattling its sabers, Washington remains silent.

Last August, The Moscow Times reported that President Putin told Turkey’s Ambassador to Moscow to “tell your dictator President he can go to hell along with his ISIS terrorists and I shall make Syria to nothing but a ‘Big Stalingrad.’” Histrionics aside, the intent is clear. Russia views Turkey as a hostile state and it will not back down.

The picture that has emerged is unsettling: Armenia is enabling a bad actor, while Russia is using it to threaten our vital interests. America’s leaders must negotiate from a position of strength. Instead, we are acquiescing to Putin’s naked show of force. The history of the 20th century shows us that this will not end well.

Mr. Ereli is the vice chairman of Mercury, a public affairs and strategy firm whose clients include the Turkish Institute for Progress. Mr. Ereli is also a former deputy spokesman of the State Department. He was U.S. Ambassador to Bahrain from 2007-2011.