Strongly and Unambiguously Sanctioning Proliferators Exploiting Nuclear Diplomacy Act of 2020 or the SUSPEND Act This bill establishes reporting and sanctions requirements related to the Treaty on the Non-Proliferation of Nuclear Weapons (NPT). Specifically, the bill requires the Department of State to report on whether parties to the NPT are fulfilling their responsibility to pursue negotiations in good faith relating to cessation of the nuclear arms race and to nuclear disarmament. Further, it requires the President, on the basis of this report, to impose sanctions against certain parties that are not meeting this responsibility.