Lawyers for the House of Representatives on Wednesday accused President Donald Trump of trying to “obstruct his own impeachment” by claiming the authority to block his advisers from cooperating with congressional investigations. The allegation came in a stinging 66-page court filing as part of the House Judiciary Committee’s bid to secure testimony from former White House Counsel Don McGahn, whom Democrats consider to be the star witness in special counsel Robert Mueller’s investigation. “A president with the power to obstruct his own impeachment through capacious grants of absolute immunity would be a president who is above the law,” House lawyers, led by House General Counsel Douglas Letter, wrote in the filing.