The Trump administration has systematically pressured the nation’s immigration judges, threatening them with disciplinary action if they do not deport more people and firing those seen as insufficiently supportive of the president’s aggressive enforcement agenda, a New York Times investigation has found.

The overhaul of the immigration courts has been far less visible than the militarized deportation raids that President Trump scaled back after public protest. But the effort has helped reshape a hugely consequential, if little-known, corner of the government that the administration is harnessing to advance its mass-deportation policies.

Although they wear robes and are required by law to exercise “independent judgment,” immigration judges are not part of the judicial branch. Instead they work for the Justice Department, under Mr. Trump’s ultimate command, and can be fired. One of their main duties is deciding whether undocumented immigrants should be deported or granted a form of legal status like asylum and be allowed to remain in the country.

So far, the Trump administration has dismissed more than 100 immigration judges out of about 750 in place when Mr. Trump returned to power, an unprecedented purge.

At the same time, the administration has reshaped the immigration bench, announcing the appointments of 143 permanent and temporary judges, including many who previously worked as immigration prosecutors for the Department of Homeland Security or as military lawyers.