John Ratcliffe, a House representative from Texas tapped by President Trump to replace Dan Coats as the director of national intelligence, has a reputation as a staunch conservative who has come to the president’s defense.

He did so most recently last week at the hearing in which Robert S. Mueller III, the former special counsel, appeared. Mr. Ratcliffe sharply questioned Mr. Mueller, accusing him of not following Justice Department guidelines after Mr. Mueller said he could not exonerate the president of obstruction of justice charges.

If a special counsel cannot bring charges, Mr. Ratcliffe argued, he should not presume to say a target was not cleared.

“So, Americans need to know this as they listen to the Democrats and socialists on the other side of the aisle as they do dramatic readings from this report,” Mr. Ratcliffe said of the part of Mr. Mueller’s report that described how the president sought to impede the investigation, adding that section of the report “was not authorized under the law to be written.”