Barr pledged that investigations would be ‘sacrosanct from political influence.’ That’s in real doubt now.

Attorney General William P. Barr faced big questions during his confirmation last year about whether he would maintain independence from President Trump when it came to the Russia investigation. To combat them, he assured senators — repeatedly — that he viewed his job as conducting investigations irrespective of the president’s political wishes.

That’s increasingly in doubt.

On Tuesday, all four prosecutors on the Roger Stone case moved to withdraw after senior Justice Department officials overrode their recommended sentence for Stone. The unorthodox move was announced shortly after Trump decried the...