In a letter sent on Friday, the senator suggested that Machen, the man whose job it would be to press the House's contempt case against Holder, was not doing his job.
Under the law, Machen doesn't have a choice in
the matter, according to Grassley, the ranking Republican on the Senate Judiciary Committee.
Grassley writes that Machen's "duty . . . shall* be to bring the matter before the grand jury for its action" and that doing so "is not optional."
And then Grassley called Machen's character into question:
"Your independence and integrity were cited as the reason that there was supposedly no necessity to appoint a special prosecutor. This matter gives you an opportunity to live up to that high praise and prove your independence. However, the way this has been handled so far suggests no such independence at all," he wrote.
The Grassley letter comes after a Department of Justice letter to House Speaker John Boehner. The Justice Department would not bring the contempt citation before a grand jury or "take any other action to prosecute" Holder, according to the letter.
*Emphasis was Grassley's
CORRECTION: An earlier version of this post misidentified the sender of a Justice Department letter. The deputy attorney general sent the letter.