President Trump told a crowd of staff from the United States Mission to the United Nations on Thursday morning that he wants to know who provided information to a whistle-blower about his phone call with the president of Ukraine, saying that whoever did so was “close to a spy” and that “in the old days,” spies were dealt with differently.

Donald F. McGahn II, the former White House counsel, defied a House subpoena on Tuesday under order of the White House, stoking outraged Democrats to contemplate anew punitive measures, including opening an impeachment inquiry, to try to enforce Congress’s oversight powers.

Through his unrelenting efforts to obstruct the Trump-Russia investigation since its inception, President Donald Trump has inflicted a slow-motion Saturday Night Massacre on the American people, a constitutional nightmare that has lasted two years instead of one night.

The Utah lawmaker Orrin Hatch, who sits on the Senate Judiciary Committee, filed a 44-page amicus brief earlier this month in Gamble v. United States, a case that will consider whether the dual-sovereignty doctrine should be put to rest. The 150-year-old exception to the Fifth Amendment’s double-jeopardy clause allows state and federal courts to prosecute the same person for the same criminal offense.

When President Trump publicly demanded that the Justice Department open an investigation into the F.B.I.’s scrutiny of his campaign contacts  with Russia, he inched further toward breaching an established  constraint on executive power: The White House does not make decisions about individual law enforcement investigations.