What is a practical alternative without a full-scale NATO deployment (questions of capability aside..)?
Their is no other practical alternative, and that is what should happen, but not just NATO. We built a coalition of the willing on other things, why not this.
Frankly there is a lot of other smaller countries around the globe that have professional forces that have a vested interest in making sure this doesn't become the norm.
Russia is not involved officially, this can be taken care of cleanly at this stage with some backbone and very little risk.