Harvard University, responding swiftly to President Trump’s proclamation barring international students from enrolling this week, asked a federal judge to block the order immediately on Thursday evening. It also filed a new claim against the administration, adding to a lawsuit the university had already filed. The White House order, issued at 8 p.m. on Wednesday, was the third time in the past month that the Trump administration has tried to use its power to ban international enrollment at Harvard in what the university has said is a violation of its First Amendment rights. In court papers, Harvard accused the White House of trying to circumvent an earlier court order that had blocked the Department of Homeland Security from banning international enrollment at Harvard. The university said that President Trump had violated the law again by invoking the executive power of the presidency against the school when the agency’s efforts had failed.