When Russia invaded Crimea in 2014, it didn’t just take a piece of Ukraine, it alerted a distracted NATO to the vulnerability of its newest member states on the eastern flank. Now, paying for the U.S. border wall with Mexico may be giving Russia another opening in Eastern Europe six years after masked Russian troops entered Ukraine.

Some $1.1 billion dedicated to strengthening the capacity of the United States to respond to Russian aggression in Europe has been redirected to the southern border wall over the last two years as the Defense Department scrambles to pay the bills for President Trump’s unfunded project.