This system creates a shield from reprisal for intelligence officials who make a so-called protected disclosure to Congress by following a process that involves filing a complaint with the intelligence community’s inspector general for initial vetting.

If the inspector general decides a complaint is credible and presents an urgent concern, the director of national intelligence is supposed to send it to Congress. If the inspector general rejects it, the whistle-blower may still then talk about it to lawmakers with protections from reprisal so long as he or she obeys rules for protecting classified information.

What protections do covered whistle-blowers have?

By law, if they follow the prescribed procedures, officials making complaints cannot be punished by their superiors as reprisal. That includes disciplinary action like being fired or demoted or being given significantly worse responsibilities or working conditions. Intelligence officers may also not lose their security clearances, the intelligence whistle-blower law adds.

These laws were written with job reprisals in mind. They were not written for, and do not cover, the highly unusual situation in which a president uses his public platform to denigrate and vaguely threaten a whistle-blower.

Do whistle-blowers have a right to remain anonymous?

Only in a limited way. Another part of the Inspector General Act says that agency watchdogs “shall not, after receipt of a complaint or information from an employee, disclose the identity of the employee without the consent of the employee, unless the inspector general determines such disclosure is unavoidable.”

In line with that law, the inspector general for the intelligence community, Michael Atkinson, did not include the whistle-blower’s name in his report to the acting director of national intelligence, Joseph Maguire. Mr. Maguire testified last week that he did not know the name of the person, whom people familiar with the matter have identified as a C.I.A. officer who was detailed to the White House at one point.

But the legal prohibition on disclosing the official’s name applies only to Mr. Atkinson. It does not bar Mr. Trump and his allies from trying to identify him or disclosing his name if they figure it out. (It would be illegal under the Intelligence Identities Protection Act for any official to disclose his name if he is a covert agent, but no one has suggested that he is.)