The 1 January messages from the president and president-elect were both short, simple and upbeat. “Happy New Year,” Donald Trump tweeted on Friday morning. “Here’s to 2021,” Joe Biden had posted as his last tweet of 2020. That’s about where the similarities ended between the lame duck Republican destined to leave the White House in less than three weeks and the incoming Democrat who will take his place. A little earlier, in dueling New Year’s Eve declarations, Trump boasted of accomplishments in office, calling them “historic victories” despite his resounding loss in November’s election and a pandemic that has never been under control and is entering its darkest phase with record deaths in parallel with chaotic early vaccine distribution. Biden praised healthcare workers on the front lines and looked ahead to his prospects of delivering what he has promised will be a transformative first 100 days in office in terms of dealing with the coronavirus, the battered economy, global re-engagement by the US and taking action on the climate crisis. After weeks of fighting to remain in office, Trump said in a video posted on Twitter in the evening on 31 December: “We have to be remembered for what’s been done.” Trump, who has yet to formally concede his November election defeat to his Democratic rival, returned to Washington early from his Florida resort amid a fight with Congress over a defence bill and coronavirus aid checks. Speaking from Rehoboth Beach, Delaware, Biden paid tribute to healthcare workers and encouraged people to get vaccinated in a brief appearance with his wife, Jill Biden, on the long-running ABC special Dick Clark’s New Year’s Rockin’ Eve with Ryan Seacrest 2021. “I’m absolutely, positively confident – confident – we’re going to come back and we’re going to come back even stronger than before,” said Biden, who takes office on 20 January. He repeated his call for vaccines to be distributed more quickly. Trump, who had Covid-19 in October, frequently played down the severity of the pandemic and oversaw a response many health experts have criticised as disorganised, cavalier and having sometimes ignored the science behind virus transmission. But in his new year remarks he noted that the US had produced a Covid-19 vaccine in record time and that he had correctly predicted it would come before the year ended. The US has been one of the countries worst-hit by Covid-19 and leads the world in fatalities, with more than 340,000 deaths officially attributed to the virus. Trump was originally scheduled to attend a New Year’s Eve party at his Mar-a-Lago resort. The White House has given no reason for why he returned to Washington early, but it coincides with Trump’s fight with Congress over his veto of a major defence bill and his demand for increased Covid-19 stimulus checks, as well as a spike in tensions with Iran. The Senate majority leader, Mitch McConnell, the top Republican in the chamber, dealt a probable death blow on Wednesday to Trump’s effort to boost coronavirus aid to Americans, declining to schedule a swift vote on a bill to raise relief checks to $2,000 from the $600 included in a $892bn relief package passed by Congress earlier this month. Trump’s fellow Republicans in Congress have largely stuck with him through four turbulent years, but he lashed out at them in recent days for not fully backing his unsupported claims of election fraud, rejecting his demand for bigger checks and moving towards the veto override. On Thursday, McConnell again rejected a vote on a standalone bill that would increase the stimulus checks, calling it “socialism for rich people” and “a terrible way to get help to families who actually need it”. The bill was passed by the Democratic-controlled House of Representatives on Monday. McConnell also said there should be nothing controversial about approving the $740bn National Defense Authorization Act (NDAA), which Trump vetoed because it does not repeal certain legal protections for tech companies. “We’ve enacted an annual NDAA for 59 straight years and counting,” McConnell said. “In the next few days – the easy way or the hard way – we’re going to do our job once again. This body will fulfil our responsibility to the men and women who protect our country.” The House voted to overturn Trump’s veto on Monday. The Senate will convene again on Friday at noon EST for a rare New Year’s Day session, in which lawmakers are expected to cast the first of two procedural votes aimed at overriding the veto. If that succeeds, the Senate is expected to hold a second procedural vote on Saturday followed by a final vote on passage. The Republican senator Josh Hawley of Missouri has said he will object to Biden’s victory when Congress convenes to officially tally the electoral college votes on 6 January, which could trigger a lengthy debate in the Senate but has no chance of overturning the results. CNN reported that about 140 Republicans in the House were expected to engage in similar tactics. Some Republican senators had supported Trump’s call for an increase in the stimulus payments, notably David Perdue and Kelly Loeffler, who face runoff elections in Georgia on 5 January that will determine which party controls the Senate under Biden. But Perdue’s campaign suffered a setback on Thursday, saying the senator was quarantining after coming into contact with someone who had tested positive for the coronavirus.