Former federal prosecutor calls Rosenstein caving into Trump's demands another case of 'getting played'
Deputy Attorney General Rod J. Rosenstein taking the oath of office inside the Department of Justice.

After President Donald Trump issued a Twitter demand to the Department of Justice Sunday, Deputy Attorney General Rod Rosenstein caved to the demand.

"If anyone did infiltrate or surveil participants in a presidential campaign for inappropriate purposes, we need to know about it and take appropriate action," Rosenstein said in a statement.

Paul Butler, former federal prosecutor and professor at Georgetown University Law Center, told MSNBC that the announcement wasn't anything new or even concerning as there has already been an investigation going on. It will now likely include these new allegations by Trump.

"I have to say what is disappointing is that we have seen Rod Rosenstein get played by the president of the United States previously," Butler said. "When the president got him to write this memo, justifying the firing of James Comey. This seems like another response to the president's political kind of instincts where I think Rosenstein is getting a little bit played."

He went on to call the expansion of the investigation a kind of "mission creep," but noted it isn't unusual.

"But, again, what is troubling is that at this point it seems to be instigated not by the new investigators new findings but by the political whims of the president," he said. He then noted that for the president to shout "jump" and Rosenstein to quickly agree is what he finds the most "concerning."

Watch his full interview below: