WASHINGTON — The Supreme Court today ruled that former President Trump is at least presumptively immune from criminal liability for his official acts, and is absolutely immune for some “core” of them — including his attempts to use the Justice Department to obstruct the results of the election. With respect to Trump’s other actions, the court left to the lower courts much of the work required to determine which are immune and which are not. At bottom, though, the court’s 6-3 majority freed presidents to use their official powers to engage in criminal acts substantially free of accountability.