President Donald Trump was accused Thursday of pushing America toward a constitutional crisis after his firing of the attorney general cast doubt over the future of an explosive probe into election collusion with Russian agents. Trump emerged from Tuesday’s midterm elections promising a new era of cooperation, but suspicions that he is trying to kill the Russia probe and an extraordinary intensification of his war with journalists has thrown Washington into turmoil. The investigation by special counsel Robert Mueller’s into whether the Trump campaign colluded with Moscow during the 2016 election has been hanging over Trump throughout his turbulent presidency. Trump has continuously threatened that he has the power to shut down what he calls “a witch hunt” and on Wednesday he took the first potential step when he replaced his attorney general, Jeff Sessions, with loyalist Matthew Whitaker. The switch, announced abruptly in a Trump tweet, provoked consternation across Washington, where politicians from both sides of the aisle have long warned that political interference in Mueller’s work cannot be tolerated. Democrats, who won the lower house of Congress in Tuesday’s midterm elections, now see Trump as close to crossing that line with the ultimate goal of covering up alleged crimes. “The rule of law is disappearing before our eyes,” tweeted Sally Yates, a deputy attorney general under Trump’s predecessor Barack Obama and briefly in the top job under Trump before he sacked her. “He wants a political crony to protect him from the investigation of his own campaign,” she said. Neal Katyal and George Conway, two prominent Washington lawyers, wrote in The New York Times that Trump was already breaking the law by appointing Whitaker without Senate confirmation. The rushed appointment “is unconstitutional. It’s illegal. And it means that anything Mr Whitaker does, or tries to do, in that position is invalid,” they argued.