They can maybe strike a couple hundred miles into Russia. They don't possess long range missiles. They retired their bombers in the early 2000's. Currently they only have fighters and attack aircraft. Which with the amount of SAM's the Russians have, an attack via air wouldn't be advisable. Ground forces could invade, but they probably lack the logistical capability to go to far from their own territory. So they lack any real capability beyond some quick raids across the border. And doing so would almost certainly trigger a massive retaliation by Russia.
Under the promise that we'd protect them.
This was in the early 90s, under pappy Bush.