Before taking over the sprawling Justice Department investigation into foes of President Donald Trump, Joe diGenova decried the lack of progress in bringing indictments.

Five months later, diGenova has left his position without charging a single case, clouding the future of an investigation that has animated right-wing commentators eager to prove an ill-defined theory of a “deep state” conspiracy to take down the Republican president.

Justice Department officials are pressing forward despite diGenova’s departure, with a flurry of subpoenas to former law enforcement and intelligence officials expected to yield grand jury testimony in the weeks ahead at the Fort Pierce, Florida, home court of a favored Trump-appointed federal judge.

Yet whether anyone ultimately will be charged, and for what, remains an open question. Investigators face not only legal hurdles and personnel upheaval but an impatient White House after more than a year of fits and starts.

The investigation known familiarly as the “grand conspiracy” case is the clearest example yet of the Trump administration’s efforts to leverage law enforcement powers to enact retribution on the president’s adversaries. The tumult that has defined the probe exposes a familiar gap between White House demands for speedy action and the Justice Department’s ability to craft the president’s litany of grievances into a prosecutable case.