What is Section 3 of the 14th Amendment? Here's how Donald Trump was disqualified by Colorado Supreme Court
The Colorado Supreme Court disqualified former president Donald Trump from holding the presidency under the Constitution's insurrection clause
The Colorado Supreme Court on Tuesday, December 19, disqualified former president Donald Trump from holding the presidency under the Constitution's insurrection clause. The court also demanded that the secretary of state exclude Trump’s name from the state's Republican presidential primary ballot.

This is the first time a court has found Trump not eligible to return to the White House considering his role in the January 6, 2021, Capitol attack. This is also the first time a presidential candidate is disqualified under the clause, Section 3 of the 14th Amendment.
What is Section 3 of the 14th Amendment?
According to constitution.congress.gov, “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.”
This is a provision that applies to people who have taken an oath to support the US Constitution. They are either "engaged in insurrection or rebellion" against the U.S. or "give aid or comfort to the enemies" of the nation. Under section 3, Congress can "remove such disability" by a two-thirds vote of the House and Senate.
The Congress passed the 14th Amendment in 1866. It was ratified by the states in 1868.
Gerard Magliocca, a law professor at Indiana University who has studied the provision, said of the Donald Trump case, “There's going to be a historical part of it and then there's going to be kind of the practical, 'where is this going to lead us' kind of discussion.”