Joe Biden will announce the first of his Cabinet picks on Tuesday, a senior aide said on Sunday, as the president-elect moves ahead with planning for his incoming administration while President Donald Trump showed no sign of abandoning his long-shot bid to overturn the U.S. election. Since Biden was declared winner of the Nov. 3 election two weeks ago, Trump has launched a barrage of lawsuits and mounted a pressure campaign to prevent state officials from certifying their vote totals, suffering another emphatic legal setback on Saturday in Pennsylvania. Ron Klain, Biden’s choice to be White House chief of staff, reiterated their camp’s call for the Trump administration – specifically a federal agency called the General Services Administration – to formally recognize Biden’s victory to unlock resources for the transition process. “I hope that the administrator of the GSA will do her job,” Klain said, referring to GSA chief Emily Murphy. Klain said the Republican president’s efforts to overturn the results were a disgrace, but also ineffectual. Biden, a Democrat, is due to take office on Jan. 20. “A record number of Americans rejected the Trump presidency, and since then Donald Trump’s been rejecting democracy,” Klain said in an interview with ABC’s “This Week” program. Klain said Biden will announce the first of his Cabinet picks on Tuesday but declined to reveal the choices. Biden said on Thursday he had selected his treasury secretary, adding his nominee will appeal to “all elements of the Democratic Party … progressive to the moderate coalitions.” Candidates on Biden’s shortlist include former Fed Chair Janet Yellen, current Fed Governor Lael Brainard, Sarah Bloom Raskin, a former Fed governor, and Raphael Bostic, president of the Federal Reserve Bank of Atlanta. Critics of Trump, including Democrats and some Republicans, have accused him of trying to undermine faith in the American electoral system and delegitimize Biden’s victory by promoting false claims of widespread voter fraud. “Fight hard Republicans,” Trump wrote on Twitter on Sunday morning as he pressed his unsubstantiated narrative of voter fraud. So far, attempts to thwart certification of vote tallies have failed in courts in Georgia, Michigan and Arizona. On Saturday, U.S. District Judge Matthew Brann, a Republican appointed by Democratic former President Barack Obama, dismissed a similar effort in Pennsylvania, writing that the case presented by Trump’s lawyers claiming voter fraud amounted to “strained legal arguments without merit and speculative accusations.” “This claim, like Frankenstein’s Monster, has been haphazardly stitched together,” Brann wrote. SOME REPUBLICANS BREAK RANKS Some of Trump’s fellow Republicans in Congress are now breaking ranks though many, including the most senior ones, have not. Republican Senator Pat Toomey on Saturday said Brann’s ruling “exhausted all plausible legal options” for Trump in Pennsylvania, and he urged the president to “accept the outcome of the election.” Toomey also congratulated Biden and Vice President-elect Kamala Harris and referred to them as “dedicated public servants.” Liz Cheney, a member of the Republican leadership team in the House of Representatives, earlier called on Trump to immediately present evidence of widespread voter fraud or otherwise respect “the sanctity of our electoral process.” Republican Senator Kevin Cramer on Sunday told NBC’s “Meet the Press” program that the start of the presidential transition process is overdue, though he still defended Trump’s continuing efforts to challenge the election and declined to recognize the Biden victory. Klain said Biden has stressed healing and bringing a divided government together, adding that there are Democrats and Republicans in Washington who want to work together. “I hope they would start to accept the reality,” Klain said of Republican leaders. He said he was encouraged by statements from Toomey and Senator Mitt Romney. “I think we’re seeing some encouraging signs,” Klain said. Critics have said Trump’s refusal to concede carries serious implications for national security continuity and in impeding the fight against the coronavirus pandemic that has killed about 256,000 Americans. Jen Psaki, a senior advisor to Biden’s transition team, said on CNN’s “State of the Union” program that legal action to compel the GSA to recognize Biden “isn’t our preference. If it was, we would’ve done it days ago because we’ve known the clear outcome for two weeks now.” Biden received 6 million more votes nationwide than Trump and, more importantly, prevailed 306-232 in the state-by-state Electoral College system that determines the election’s victor. For Trump to have any hope of remaining in the White House, he needed to somehow overcome Biden’s 81,000-vote margin in Pennsylvania, a state he won in 2016. The state is due to begin certifying its results on Monday.