WASHINGTON — The complaints came to the National Security Council’s top lawyer within hours of each other in early July. Two senior aides said they feared that one of President Trump’s top political appointees was improperly pressuring Ukrainian officials to help the president’s political fortunes.

The lawyer, John A. Eisenberg , remained impassive, taking notes as the aides conveyed their concerns, according to congressional testimony released Friday. He promised one official he would follow up and shared the complaints with the White House counsel, who advised him to raise them with Mr. Trump.

But instead of briefing the president, Mr. Eisenberg and his deputy decided that while the efforts of the appointee — Gordon D. Sondland , the ambassador to the European Union — were unorthodox, they were not criminal , according to a person briefed on their decision. Mr. Eisenberg set aside the concerns of the senior aides, one of whom who would go on to describe Mr. Sondland to impeachment investigators as a national security risk because he was so unprepared for his job.

Mr. Eisenberg would come to the same conclusion again and again when confronted with revelations that Mr. Trump had ordered up a shadow Ukraine policy to advance his personal interests: However disturbing the facts, no one involved violated the law.