Exceeded their authority when they left insurrectionist Trump on the ballot. Amendment XIV
Section 3; No person shall be a Senator or Representative in Congress, or elector of President and Vice President, or hold any office, civil or military, under the United States, or under any state, who, having previously taken an oath, as a member of Congress, or as an officer of the United States, or as a member of any state legislature, or as an executive or judicial officer of any state, to support the Constitution of the United States, shall have engaged in insurrection or rebellion against the same, or given aid or comfort to the enemies thereof. But Congress may by a vote of two-thirds of each House, remove such disability. Note the last sentence in section 3: "But Congress may by a vote of two-thirds of each House, remove such disability."; Not the Supreme Court's approval, but Congress's approval is required to allow an insurrectionist on the ballot. Not a simple majority but a two-thirds majority requirement.
