Illegally! Amendment 13, 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.

No such vote was held. The disability was not removed. Allowing the tried and convicted impeached and indicted insurrectionist Donald Trump to appear on any ballot for any public position, State or Federal, after he was convicted impeached and indicted of for insurrection against the United States was the beginning of the Constitutional crisis we are now mired in and all of Congress is complicit.

Edited: a word. I don't give a flying fuck what the corrupted kangaroo circus in DC voted reality was. Anyone able to tie their own shoes who lived through that event knows what the truth is.