The US supreme court has unanimously rejected a baseless lawsuit filed by Texas seeking to overturn the presidential election result, dealing the biggest blow yet to Donald Trump’s assault on democracy. In a brief, one page order, all nine justices on America’s highest court dismissed the longshot effort to throw out the vote counts in four states that the president lost: Georgia, Michigan, Pennsylvania and Wisconsin. The decision hammers another nail in the coffin of Trump’s increasingly desperate effort to subvert the will of the people and deny Joe Biden the presidency. The suit filed by Ken Paxton, the Texas attorney general, sought to invalidate the results in four swing states, asking the court to extend the deadline for election certification so alleged voting irregularities could be investigated. It was backed by Donald Trump, 17 other states and 126 Republicans in the House of Representatives – more than half the caucus – including the House minority leader, Kevin McCarthy of California, and the minority whip, Steve Scalise of Louisiana. Trump had long expressed hope that a disputed election would go before the supreme court, to which he appointed three justices during his term, ensuring a 6-3 conservative majority. Earlier on Friday he tweeted: “If the Supreme Court shows great Wisdom and Courage, the American People will win perhaps the most important case in history, and our Electoral Process will be respected again!” But hours later, his hopes of a political miracle were all but extinguished. The supreme court wrote: “The State of Texas’s motion for leave to file a bill of complaint is denied for lack of standing under Article III of the Constitution. Texas has not demonstrated a judicially cognizable interest in the manner in which another State conducts its elections. All other pending motions are dismissed as moot.” Officials in Michigan, Pennsylvania, Georgia and Wisconsin had derided the suit as a publicity stunt. More than 20 other attorneys general from states including California and Virginia also filed a brief on Thursday urging the court to reject the case. Josh Shapiro, the attorney general of Pennsylvania, welcomed the court’s ruling. “Our nation’s highest court saw through this seditious abuse of our electoral process,” he tweeted. “This swift denial should make anyone contemplating further attacks on our election think twice.” Democrats in Congress also expressed gratitude. Eric Swalwell of California tweeted: “The Supreme Court, a mix of conservative and liberal members, united to defend your vote against @realDonaldTrumpand his democracy deniers in Congress.” And Senator Ben Sasse, one of relatively few Republicans to acknowledge Biden’s victory, signalled that it was time for the party and government to move on. He said: “Since Election Night, a lot of people have been confusing voters by spinning Kenyan Birther-type, ‘Chavez rigged the election from the grave’ conspiracy theories, but every American who cares about the rule of law should take comfort that the Supreme Court – including all three of President Trump’s picks – closed the book on the nonsense.” Courts have dismissed numerous of lawsuits and appeals by the Trump campaign and its allies in various states. William Barr, the attorney general and a staunch Trump ally, has said the justice department uncovered no evidence of widespread voter fraud that could change the outcome of the election. Saturday will mark the 20th anniversary of the court resolving the 2000 election in Republican George W Bush’s favour but that was a much closer contest that came down to one state: Florida. Biden gained 306 votes in the electoral college – the same as Trump in 2016 – and leads the national popular vote by 7m. Some Democrats have accused Trump and his Republican backers of sedition. Chris Murphy, a senator for Connecticut, said in a floor speech on Friday: “Those who are pushing to make Donald Trump president for a second term, no matter the outcome of the election, are engaged in a treachery against their nation.”