Alaska Republican senator Lisa Murkowski said on Sunday she would not support efforts to confirm Donald Trump’s third supreme court pick before the presidential election on 3 November. The move came a day after Susan Collins of Maine, another Republican moderate, took the same position.Senate majority leader Mitch McConnell can now afford to lose only one more senator if he is to achieve his aim of tilting the court firmly to the right for a generation or more.Thanks to reforms initiated by Democrats in 2013 but completed by Republicans in 2017, a simple Senate majority is required to confirm a supreme court justice.Murkowski and Collins’ statements mean that if no Democrats or independents come over to the Republican side, McConnell can count on a win by 51 votes to 49. He could afford to lose one more senator, as Vice-President Mike Pence would break any tie.The Senate majority leader is looking to hold a vote before election day – or even in the lame duck period after the election and before the next presidential inauguration, on 20 January, even if Democrats take the White House and the Senate.A seat on the nine-member court fell open with the death on Friday night of Ruth Bader Ginsburg, of pancreatic cancer and at the age of 87.We need to begin thinking about the credibility and integrity of our institutionsLisa Murkowski – in 2018Trump has already named Neil Gorsuch and Brett Kavanaugh to the court, but they were conservatives who replaced conservatives. A rightwing replacement for Ginsburg, a heroine to liberals, would weight the court 6-3 in favour of conservatives.Ginsburg’s family said the justice had wished not to be replaced before the election, which is less than 50 days away and for which some states have begun early voting.McConnell immediately disregarded that wish, vowing to advance a Trump nominee.His opponents immediately cried foul, over McConnell’s refusal in in 2016 to sanction even a hearing for Merrick Garland, Barack Obama’s nominee to replace Antonin Scalia, who died in February that year. McConnell argued then that a vacancy should not be filled in the final year of a presidency.On Saturday, Collins said she did not support moves to vote on any nominee before an election. That evening, Trump told a rally in North Carolina he would nominate a woman, promising to reveal the name in the coming days.Murkowski had already indicated her opposition to a vote so close to the election. In a statement on Sunday, she made it official.“For weeks,” she said, “I have stated that I would not support taking up a potential supreme court vacancy this close to the election. Sadly, what was then a hypothetical is now our reality, but my position has not changed.“I did not support taking up a nomination eight months before the 2016 election to fill the vacancy created by the passing of Justice Scalia. We are now even closer to the 2020 election – less than two months out – and I believe the same standard must apply.”Republicans insist the Garland precedent does not apply, because their party holds both the Senate and the White House. But there is no constitutional provision which says a president and Senate of different parties cannot confirm a justice. Clarence Thomas, a staunch conservative on the current court, was the last justice confirmed by a Senate held by the party opposing the president.If the Democratic candidate Mark Kelly wins a special election in Arizona, he could be seated by 30 November, producing a tie if a vote has not already been held.More immediately, Republicans either vulnerable to re-election defeat, like Collins, or less likely to toe the Trumpist line than most, like Murkowksi, are being watched closely.Cory Gardner of Colorado is struggling in his re-election race, while Thom Tillis is in a tight fight in North Carolina.Lamar Alexander of Tennessee is both relatively collegially minded and retiring, so relatively free of pressure.Mitt Romney of Utah is a former presidential candidate with one eye on his place in history, the son of a governor who cited his father, his conscience and fidelity to the constitution when he became the sole Republican to vote for Trump’s impeachment. More