There’s no reason why House Democrats could not have pursued lawsuits to compel compliance with all of the subpoenas while at the same time maintaining the brisk pace of impeachment thus far. Courts can move quickly—but only if asked.
Democrats might be betting that widespread defiance of subpoenas at the president’s behest bolsters the case for an article of impeachment for obstruction of justice. Another concern might be that, even if courts rule swiftly and consistently that former and current employees lack blanket immunity from testifying, some might still show up and refuse to speak on the basis of executive privilege—leaving Congress empty-handed despite protracted litigation.
Nevertheless, the House should fight hard for access to the full story about the president’s Ukraine shenanigans, and not let the executive branch win by default. Some current and former executive-branch officials, including Ambassador Gordon Sondland and former National Security Counsel expert Fiona Hill, have testified in spite of White House efforts to stonewall Congress. Others, including former Ukrainian ambassador Marie Yovanovitch, have done so despite intimidating tweets from the president of the United States. Aggressive litigation on all subpoenas would persuade more witnesses to do the same, while showing support for the courageous people who have already complied.