WASHINGTON (AP) — The U.S. House is ready to impeach Homeland Security Secretary Alejandro Mayorkas over border security, a deeply partisan and highly unusual attack on a Cabinet official that has drawn concerns from constitutional scholars and rebuke from Democrats.

Republicans in the House argue that Mayorkas has “refused to comply” with immigration laws resulting in the record surge of immigrants at the U.S.-Mexico border and “breached the public trust” by his actions and comments. The House vote on the charges, which Democrats say are untrue and hardly grounds for impeachment, is set for Tuesday.

Not since 1876 has a Cabinet secretary faced impeachment charges and it’s the first time a sitting secretary is being impeached — 148 years ago, Secretary of War William Belknap resigned just before the vote.

“Very clearly Secretary Mayorkas has picked and chosen which laws he’s going to enforce,” said Rep. Mark Green, R-Tenn., the chairman of the Committee on Homeland Security, at a hearing ahead of the vote.

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The impeachment charges against Mayorkas come as border security is fast becoming a top political issue in the 2024 election, a particularly potent line of attack being leveled at President Joe Biden by Republicans, led by the party’s front-runner for the presidential nomination, Donald Trump.

Record numbers of people have been arriving at the southern border, many fleeing countries around the world, in what Mayorkas calls an era of global migration. Many migrants are claiming asylum and being conditionally released into the U.S., arriving in cities that are underequipped to provide housing and other aid while they await judicial proceedings which can take years to determine if they may remain.

The House Democrats are expected to unite against the two articles of impeachment against Mayorkas, calling the proceedings a sham over charges that do not rise to the Constitution’s bar of treason, bribery or “high crimes and misdemeanors.”

“This is a total waste of time,” said Rep. Joe Neguse, D-Colo., at Monday’s hearing.

The impeachment of Mayorkas landed quickly onto the House agenda after Republican efforts to impeach Biden over the business dealings of his son, Hunter Biden, hit a lull, and the investigation into the Biden family drags.

Green’s committee had been investigating the Homeland Security secretary for much of the past year, but a resolution from Rep. Marjorie Taylor Greene, R-Ga., a Trump ally, pushed it to the fore. The panel swiftly held a pair of hearings in January before announcing the two articles of impeachment against Mayorkas.

A former federal prosecutor, the secretary never testified on his own behalf, but submitted a rare letter to the panel defending his work.

Tuesday’s vote arrives at a politically odd juncture for Mayorkas, who has been shuttling to the Senate to negotiate a bipartisan border security package, earning high marks from a group of senators involved in the effort.

The legislation, which emerged Sunday and is heading for a test vote Wednesday, is one of the most ambitious immigration overhauls in years. But other Republicans are panning the bipartisan effort, and House Speaker Mike Johnson, R-La., says it’s “dead on arrival.”

It’s not at all clear that Johnson, with one of the smallest House majorities in modern times, has the support of almost all Republicans needed to impeach Mayorkas. A few holdouts remained ahead of the scheduled vote.

Even if Republicans are able to impeach Mayorkas, he is not expected to be convicted in a Senate trial where Republican senators have been cool to the effort. In fact, the Senate may simply refer the matter to a committee for its own investigation, delaying immediate action.

Impeachment, once rare in the U.S., has been used as both a constitutional check on the executive but also increasingly as a political weapon.

The House Republicans have put a priority this session of Congress on impeachments, censures and other rebukes of officials and lawmakers, setting a new standard that is alarming scholars and others for the ways in which they can dole out punishments for perceived transgressions.

Experts have argued that Mayorkas has been snared in a policy dispute with Republicans who disapprove of the Biden administration’s approach to the border situation.

Constitutional law expert Jonathan Turley said impeachment is not to be used for being “a bad Cabinet member.” Lawyer Alan Dershowitz wrote, “Whatever else Mayorkas may or may not have done, he has not committed bribery, treason, or high crimes and misdemeanors.”

“This impeachment is exactly what impeachment was never supposed to be for,” said Deborah Pearlstein, director of the Princeton Program on Law and Public Policy who testified before the panel, in an interview.

Trump as president was twice impeached — first in 2019 on corruption over his phone call with the Ukrainian president seeking a favor to dig up then-rival Biden, and later on the charge of inciting the Jan. 6, 2021 insurrection at the Capitol. He was acquitted on both impeachments in the Senate.

Belknap, who was impeached over a kickback scheme in government contracts, was acquitted in the Senate trial.