Not to mention it would really piss of the few allies we have left who have put billions of dollars into it themselves.
That said it does have limited mobility. It was repositioned for the launch of the Soyuz capsule yesterday. It could be nudged into a lower orbit that would speed decay but its pointless anyway because its an idiotic idea.
The point was not to suggest any action, the point was to emphasize the full and complete control of the ISS held by the U.S. What is idiotic is the rash responses on FR these days by people who only superficially read a post without grasping the full message. So here is my comment again using lots more unnecessary words:
The U.S, has the ability to control nearly every system on the ISS from the ground, they can turn the lights on and off in nearly every compartment they control the environmental settings, heating, cooling, waste treatment everything you could imagine. They control the thrusters for reorienting the entire station for spacecraft access and convenience, and they can move it into higher and lower orbits to avoid known space debris. In the 1970s due to unexpected sunspot activity the first American space station Skylab's orbit started to decay faster than expected and the US had no operational spacecraft - manned or unmanned -- or other ability to boost Skylab in its orbit. As Skylab's orbit decayed there was a great fear that once it burned up larger sections could come down over populated areas and injure or kill people. Ultimately it came down over the Indian Ocean and Western Australia and no one was injured. However to avoid that problem in the future large NASA orbiting facilities including ISS have been launched in recent years with maneuvering thrusters and ample fuel to allow for a controlled reentry if such a thing were ever necessary; i.e dropping it in the Pacific Ocean. Because of all of these abilities at the fingertips of NASA flight controllers it would be foolhardy for the Russians to ever attempt to seize control of the ISS or attempt to ban Americans from using it.
Or... in response to the question of Russian blocking the US I could have emphasized the extent of the control the US has of the station by stating, "NASA has the ability to drop the ISS into the Pacific Ocean any time they want to. Which I did. There was a time on FR when you didn't need to write a couple hundred words to make a simple point.