People attend Supreme Court oral arguments last year in Washington. An expected filing to the court by Donald Trump would preserve a delay on what would be a landmark criminal trial of a former president while the nation’s highest court decides what to do. — AP File Photo/J. Scott ApplewhiteWASHINGTON — Former President Donald Trump is asking the Supreme Court to extend the delay in his election interference trial, saying he is immune from prosecution on charges he plotted to overturn his 2020 election …