In a series of partisan votes on Wednesday, the Democratic-majority U.S. Senate dismissed impeachment charges against Department of Homeland Security Secretary Alejandro Mayorkas, bringing a swift end to the GOP's attempt to oust him. The move highlights the stark divide between Democrats, who saw the impeachment as political theater, and Republicans, who argue that dismissing the charges without a full trial sets a dangerous precedent.

Senators voted along party lines to rule the articles of impeachment unconstitutional for not meeting the standard of high crimes and misdemeanors. Sen. Lisa Murkowski (R-Alaska) voted present on the first article, while the rest of her Republican colleagues voted against the articles being unconstitutional. Both impeachment articles were declared unconstitutional by a vote of 51 to 48 and 51 to 49.

The House had made Mayorkas the first cabinet official to be impeached in over 150 years in February, charging him with breach of public trust and failing to uphold U.S. laws. However, Democrats argued that Mayorkas was impeached because of policy disputes and not any high crimes or misdemeanors.

The dismissal of the impeachment effort was a tough vote for Democrats facing competitive races in November, as Republicans have made border security and immigration their top campaign issue this year. Sens. Jon Tester (D-Mont.), Jacky Rosen (D-Nev.), Sherrod Brown (D-Ohio), and Bob Casey (D-Pa.) all voted against the impeachment effort despite facing reelection.

An effort to reach a deal to allow Republicans time to debate the articles of impeachment before the motion to dismiss fell apart, with Sen. Eric Schmitt (R-Mo.) objecting. Senate Majority Leader Chuck Schumer (D-N.Y.) then moved to dismiss the charges on the basis that they are not constitutional.

The White House and congressional Democrats blasted the impeachment exercise as a misuse of impeachment powers to highlight a policy dispute, rather than addressing the standard of "high crimes and misdemeanors." White House spokesperson Ian Sams chastised House Republicans for staging "baseless political stunts while killing real bipartisan border security reforms."

House Speaker Mike Johnson, in a joint statement with fellow top Republicans, said "every single Senate Democrat has issued their full endorsement of the Biden administration's dangerous open border policies." The U.S. Border Patrol made more than 1 million arrests of migrants crossing the U.S.-Mexico border illegally in the past six months, according to internal agency statistics reviewed by Reuters, a pace similar to record-breaking totals during Biden's first three years in office.

Mayorkas, a former federal prosecutor born in Cuba, maintains that the record numbers of migrants arriving at the U.S.-Mexico border over several months stem from Congress' inability to reform antiquated laws. The effort to impeach him was just the second time in history that a member of a president's cabinet was impeached by the House, with the last instance occurring in 1876.

Top Senate Republican Mitch McConnell had called for a "thorough consideration" of the charges against Mayorkas, arguing that disposing of the case without a trial would mean "running away both from our fundamental responsibility and from the glaring truth of the record-breaking crisis at our southern border."

As the impeachment effort comes to an end, the partisan divide over border security and immigration remains a central focus in the lead-up to the November elections. The dismissal of the charges against Mayorkas is likely to fuel further debate and controversy surrounding the Biden administration's handling of the situation at the U.S.-Mexico border.