Former Trump adviser Bolton threatened to sue if subpoenaed to testify in impeachment probe: committee

U.S. President Donald Trump's former national security adviser, John Bolton, threatened to sue if congressional committees issued a subpoena to compel him to testify in their impeachment probe, a House of Representatives committee said on Thursday. Bolton had been asked to appear for testimony behind closed doors on Thursday, but failed to appear. "His counsel has informed us that unlike three other dedicated public servants who worked for him on the NSC (National Security Council) and have complied with lawful subpoenas, Mr. Bolton would take us to court if we subpoenaed him," an official of the House of Representatives Intelligence committee said.