WASHINGTON — In the annals of cutthroat Washington politics, it would be hard to find a cabinet secretary left abandoned and humiliated in the way President Trump has left Attorney General Jeff Sessions.

After days of questioning Mr. Sessions’s decisions, Mr. Trump all but signed his political death warrant on Tuesday by dismissing the attorney general as “VERY weak,” perhaps the most cutting assessment for a president who prizes strength above all else. He made no effort to dispel the impression that he wants Mr. Sessions out. “We will see what happens,” he told reporters. “Time will tell.”

The consequences go beyond the fate of one cabinet officer. In escalating his unforgiving campaign against Mr. Sessions, Mr. Trump opened a rift with conservatives who see the attorney general as their champion. And he put the White House in a virtual state of war with the Justice Department amid a high-stakes investigation in a way that it has not been since President Richard M. Nixon’s administration.

Even if the standoff does not end in Mr. Sessions’s departure — and the conventional wisdom in Washington assumes it will eventually — the spectacle raised questions about the future of the investigation into Russia’s election interference, led to criticism from conservative news organizations that are usually deferential to the president and left Republican lawmakers unsettled as they defended the attorney general.