Wholeheartedly agree with your choice of engine. But the way to bump the interloper is to attach the engine to smaller (but still substantial) body, and use that to whack it. Of course, that capability will be frowned upon, from the political standpoint, because it can easily be weaponized. Using smallish asteroids to destroy cities is easier and cheaper than building a nuclear program, and the result can look like an act of nature.
Nudging the body is only the first part of the plan. The electric motors will continue to fire until the body is captured into a convenient orbit such as the L-4 or the L-5 libration point. Depending on composition, it might have some mineral value or simply mass value.