Micheal Baca has become the third Colorado presidential elector to join a federal lawsuit against Secretary of State Wayne Williams alleging Williams violated their constitutional rights by making threats and removing Baca as an elector ahead of the high-drama 2016 Electoral College vote.

“Our objective is to affirm a constitutional principle,” Baca, who was replaced after voting for Ohio Gov. John Kasich instead of Hillary Clinton, said in a statement. “That principle is critical to our Framers’ design for electing the president. It is critically important that the courts clarify the rights of electors, so that the uncertainty that surrounded the 2016 vote does not repeat itself in the future.”

The lawsuit was announced in August by Equal Citizens, an advocacy group founded by Harvard law professor Lawrence Lessig, and filed on behalf of two Democratic electors, Polly Baca (unrelated to Micheal) and Robert Nemanich.

The electors in the lawsuit have argued that the U.S. Constitution gives presidential electors the right to vote their conscience.

“The Constitution vests in electors the choice for whom they will vote,” Lessig said in a news release Wednesday announcing Baca has joined the lawsuit. “Subject to a single limitation specified by the Constitution, that discretion is reserved to them, and them alone. When Secretary Williams removed Micheal Baca as an elector because of his vote, Williams violated both Baca’s federal constitutional rights and a clear directive of the 10th Circuit (Court of Appeals). We will ask the federal courts to affirm the Constitution’s plan by declaring that the actions of Secretary Williams violated plaintiffs’ rights.”

Lessig and Denver lawyer Jason Wesoky are representing the electors in the case. They are seeking $1 in damages.

The lawsuit is the latest among a flurry of challenges to Colorado’s electoral rules filed in the wake of Donald Trump’s election. Those rules require presidential electors to vote for the winner of the state’s popular vote. Clinton bested Trump in Colorado during last year’s election.

The Electoral College process took on new importance — and drama — after Trump’s victory because a group of Democratic electors had sought to band together with Republicans to deny Trump the 270 electoral votes he needed to become president.

That effort failed but turned Colorado into an unlikely ground zero for a broader debate about the role of the Electoral College.

Polly Baca and Nemanich voted for Clinton, as the law requires. The Colorado Attorney General’s Office was forwarded Micheal Baca’s case for prosecution but ultimately decided against charging him.

The Colorado Secretary of State’s Office has said the Equal Citizens lawsuit is without merit.