WASHINGTON — The Trump administration tried and failed on Tuesday to secure an indictment in connection with a video featuring six Democratic lawmakers urging members of the military and intelligence communities not to comply with unlawful orders, three sources familiar with the matter told NBC News.

It was not clear how many of the lawmakers the Trump administration attempted to indict, or if the failed attempt will be addressed in a future court hearing.

The indictment pursued by the office of U.S. Attorney for the District of Columbia Jeanine Pirro is the latest example of the Justice Department targeting the president’s perceived political opponents. The government attorneys assigned to the case are political appointees, not career Justice Department prosecutors, according to a source familiar with the investigation.....

In addition to the First Amendment issues, the “speech or debate" clause of the Constitution gives lawmakers on Capitol Hill immunity from prosecution for acts taken within the legislative sphere, a fundamental check on the constitutional separation of powers.

Several Democrats involved in the video recently said they would not cooperate with the Justice Department's probe into the video.

Under longstanding Justice Department policy, the Public Integrity Section would normally have to sign off on every step of an investigation into a sitting member of Congress, especially a case with free speech and speech and debate considerations. But the Trump administration has dismantled the Public Integrity Section, eliminating checks meant to prevent the Justice Department's powers from being abused for political purposes.