Supplying Ukraine with Provisions to Protect against Ongoing Russian Threats Act or the SUPPORT Act This bill states that it is U.S. policy to take necessary and appropriate steps to support Ukraine's efforts to reassert control of its territory and defend its sovereignty in the event of a Russian invasion of Ukraine, including by providing lethal and nonlethal assistance and sharing intelligence. The bill also requires the Department of Defense to report to Congress a plan for providing such support to a Ukrainian insurgency. The National Intelligence Council must produce an intelligence community assessment relating to Russia's gray zone activities and assets. (Under this bill, a gray zone activity is an activity to advance a foreign state's interests that (1) falls between ordinary statecraft and open warfare, (2) is designed to maximize the advancement of such interests without provoking a U.S. kinetic military response, and (3) falls on a spectrum ranging from covert adversary operations to open adversary operations.