Defense Secretary Ash Carter said this week that the U.S. faces a world of expanding security threats, and we’d add that those include the rising authoritarian states that want to dominate their regions—Iran, China and Russia. So we’re glad to see the Obama Administration finally doing more to secure NATO’s eastern front against Russia.

The White House announced Tuesday that its fiscal 2017 budget includes $3.4 billion for the Pentagon’s European Reassurance Initiative, or ERI, up from $789 million. The Pentagon launched the ERI in 2014 following Russia’s illegal annexation of Crimea.

The breakthrough in this year’s budget is that the Pentagon plans to outfit and deploy a brigade-size force that will rotate positions across NATO’s front line, including in Poland and the Baltics. The brigade will be combat-ready and able to call on heavy equipment that will be pre-positioned on the Continent.

The combat brigade represents a substantial improvement on the current deployment of about 150 U.S. soldiers rotating into Poland and each of the Balts for joint training. A brigade couldn’t stop an armored invasion, but it certainly could deter and respond to the kind of “little green men” invasion that Vladimir Putin deployed in Crimea and eastern Ukraine.

The U.S. commitment should reassure NATO’s eastern members, especially the Baltic states that Mr. Putin believes should never have left the Soviet Union. Poland could also use some reassurance, especially given that it is one of the few NATO members that is meeting its commitment to spend at least 2% of GDP on defense. Lithuanian Foreign Minister Linas Linkevičius called the new commitment “a coming back to Europe” for the U.S. “It is as it should be, and very important for Euro-Atlantic security.”