First the United States pulls out of the INF treaty and now the New START treaty is at risk. Russia wants to reject extending the time on the New START treaty and wants to possibly pull out. The treaty would expire in February 2021, so if a new United States administration is going to take over the office there would be no way in convincing Russia to renew the treaty. The new start treaty limits the nuclear weapons and systems that are used.
If Russia pulls out of the New START treaty before it expires then it is possible that this current administration could follow.