The Senate quickly dispensed with the two impeachment charges against Department of Homeland Security Secretary Alejandro Mayorkas, convening a short-lived trial Wednesday that brought an end to a months-long effort to punish the secretary for his handling of the southern border.

The Senate's 51-member Democratic majority voted to dismiss both charges as unconstitutional over the objections of Republican members. The entire proceeding lasted just three hours.

Mayorkas became just the second Cabinet secretary in U.S. history to be impeached when the House charged him in February with "willful and systemic refusal to comply with the law" and a "breach of public trust." Democrats strongly opposed the impeachment effort, decrying it as a political stunt and saying the allegations constituted a policy disagreement that fell far short of the constitutional threshold for impeachment.

"We felt very strongly that we had to set a precedent that impeachment should never be used to settle policy disagreements," Senate Majority Leader Chuck Schumer said Wednesday evening. "If we allowed that to happen, it would set a disastrous precedent for Congress — could throw our system of checks and balances into cycles of chaos." 

Under the Constitution, the Senate is responsible for holding a trial to determine if impeached officials are guilty and should be removed from office. The House transmitted the articles on Tuesday, and senators were sworn in as jurors Wednesday afternoon. Sen. Patty Murray, a Washington Democrat and the president pro tempore of the chamber, presided over the trial. Senators took turns signing an oath book, an indication of the gravity of the proceedings.

The outcome of the trial was a foregone conclusion, given the Democratic control of the chamber. Nonetheless, Senate Republicans called on Democratic leaders to hold a comprehensive trial, and a handful of GOP lawmakers attempted to delay the proceedings. When Schumer tried to move forward with an agreement to allow for a period of debate after senators were sworn in, Missouri GOP Sen. Eric Schmitt objected, accusing Schumer of "setting our Constitution ablaze" by refusing to hold a full trial.

Without the agreement, Schumer then opted for a different path forward — asking senators to vote on a point of order over whether the first impeachment charge met the threshold of "high crimes and misdemeanors" outlined in the Constitution. The move effectively blocked Senate Republicans from presenting their own points of order, which could have derailed the proceedings further.

Senators ultimately voted 51-48 along party lines that the first impeachment article was unconstitutional, with Sen. Lisa Murkowski, an Alaska Republican, voting present. On the second article, senators voted 51-49, with Murkowski joining her fellow Republicans. 

Before the votes, Sen. Ted Cruz, a Texas Republican, argued that Schumer presented no evidence that the charge was unconstitutional and motioned to move the impeachment trial into a closed session for debate. His motion fell short. 

"The majority leader's position is asking members of this Senate to vote on political expediency to avoid listening to arguments," Cruz said. "The only rational way to resolve this question is actually to debate it, to consider the Constitution and consider the law."

A number of other Senate Republicans took turns offering different motions Wednesday afternoon to delay an end to the trial. But each fell short in the Democratic-controlled chamber.

Mia Ehrenberg, a DHS spokesperson, said in a statement that the Senate's decision to reject the impeachment articles "proves definitively that there was no evidence or Constitutional grounds to justify impeachment."

Alan He contributed reporting.