WASHINGTON - U.S. President Donald Trump's increasingly tenuous efforts to reverse his election loss to President-elect Joe Biden could be dealt a lethal blow on Monday, as Biden turns to the task of building his cabinet.

Michigan is set to certify its results Monday, and Pennsylvania is likely to move a step closer to doing so.

Trump, a Republican, lost both battleground states in the Nov. 3 election, but he has refused to concede defeat and has, instead, launched a legal battle to overturn the results there and in other close races across the country.

Trump's hopes of preventing the Democrat Biden from taking office on Jan. 20 likely will be doomed if Michigan and Pennsylvania certify their results, confirming Biden as the winner of a combined 36 electoral votes. Biden won 306 electoral votes, 36 over the 270 threshold needed to win the White House.

It remains unclear whether the process in Michigan will work as state law dictates. Michigan's canvassing board, which is evenly split between two Democrats and two Republicans, will meet on Monday to decide whether to certify the results.

Biden defeated Trump in Michigan by more than 150,000 votes, and the board is required by law to validate the count.

But a Republican member of the board, Norman Shinkle, has suggested in recent media interviews that he favors delaying certification because of technical irregularities. Officials in one county noted irregularities that may have affected a few hundred votes, and the Trump campaign has suggested that points to widespread fraud.

A deadlock on moving ahead with certification would likely force the matter into state appeals courts, where an order would be sought to compel the board to perform its function. If the members refused, Governor Gretchen Whitmer, a Democrat, has the authority to replace them.

Monday is also the deadline in Pennsylvania for counties to report their certified tallies to Secretary of State Kathy Boockvar, a Democrat. Boockvar likely would then certify the results on behalf of the state in a matter of days. Biden won Pennsylvania by more than 80,000 votes.

Trump's push to delay certification in several states has met with failure, most recently on Saturday, when a federal judge in Pennsylvania dismissed a Trump campaign lawsuit, saying it was not in the court's power to violate the Constitution.

BIDEN CABINET

Biden, working in his home state of Delaware, has pushed ahead with his transition plans despite the lack of cooperation from the current administration. Ron Klain, the incoming White House chief of state, said on Sunday that Biden will announce his first Cabinet picks on Tuesday.

Joe Biden will pick Antony Blinken as U.S. secretary of state, a person close to the president-elect's transition said on Sunday, elevating one of his most seasoned and trusted aides as he prepares to undo Trump's "America First" foreign policy. 

Blinken's appointment makes another longtime Biden aide with a foreign policy background, Jake Sullivan, the top candidate to be U.S. national security adviser.

The President-elect has chosen another veteran diplomat, Linda Thomas-Greenfield, who held a top diplomatic post in the administration of former President Barack Obama, as U.S. ambassador to the United Nations, media reports said on Sunday. 

Biden said last week he had chosen a Treasury secretary, and would announce the winner near Thanksgiving, Nov. 26. Former Federal Reserve chief Janet Yellen is said to be the top candidate.

MORE RECOUNTS, AUDITS TO COME

Meanwhile, Trump's focus remains on his quixotic quest to overturn the election.

Trump's push to delay certification in several states has met with failure, most recently on Saturday, when a federal judge in Pennsylvania dismissed a Trump campaign lawsuit, saying it was not in the court's power to violate the Constitution.

Ahead of Monday's vote by Michigan's canvassing board, Republican National Committee Chairwoman Ronna McDaniel, a Trump ally, and Michigan Republican Party Chairwoman Laura Cox wrote a letter urging the board to conduct an audit before certification.

Trump's campaign has also filed a petition for another recount in Georgia, which on Friday certified results showing Biden had narrowly won that state, a longtime Republican bastion in presidential elections.

While most Republicans continue to either publicly back Trump's efforts or remain silent, a steadily growing chorus is imploring him to concede the election and assist with the transition to Biden's administration.

Republican Senator Lisa Murkowski tweeted on Sunday that "it is time to begin the full and formal transition process," noting the courts had so far found Trump's legal claims without merit and that the pressure campaign on state legislators "is not only unprecedented but inconsistent with our democratic process."

Electors in each state will convene as a so-called "Electoral College" on Dec. 14 to formally select the next president.

(Reporting by James Oliphant; Additional reporting by Trevor Hunnicutt; Editing by Paul Simao and Christopher Cushing)