Matthew Whitaker was appointed acting attorney general after Jeff Sessions resigned Wednesday.

He's taken over Special Counsel Robert Mueller's investigation, according to Bloomberg News.

President Donald Trump wants to end the investigation, and Whitaker thinks it should be limited in scope.

Whitaker previously outlined a plan to keep Mueller's investigation on a tight leash by defunding it.

Matthew Whitaker was appointed as acting attorney general by President Donald Trump Wednesday. Whitaker now has control of Special Counsel Robert Mueller's investigation into Russian interference in the 2016 presidential election, according to Bloomberg News.

Whitaker has said he wants to curtail the limits of Mueller's investigation, and wrote an op-ed for CNN about it 2017. And Trump himself has attacked he investigation and commanded the Justice Department to end it.

But if he wants to restrain the investigation, Whitaker doesn't need to fire Mueller or end it outright. As he outlined in an interview with CNN in July 2017, he can simply use his power as America's chief law enforcement officer to defund it.

"I could see a scenario where Jeff Sessions is replaced with a recess appointment," Whitaker said. "And that attorney general doesn't fire Bob Mueller, but he just reduces his budget to so low that his investigation grinds to almost a halt."

Read more: Jeff Sessions' replacement is good news for Trump and bad news for Mueller.

Now that he's replaced Jeff Sessions as a recess appointment, Whitaker himself is exactly in the position he speculated about.

Whitaker suggested Rod Rosenstein, the deputy attorney general — who oversaw the Mueller investigation because of former Attorney General Jeff Sessions's recusal — could pursue that strategy at Trump's request.

"I think what ultimately the president is going to start doing is putting pressure on Rod J. Rosenstein, who is in charge of this investigation, his acting attorney general," Whitaker told CNN. "And really try to get Rod to maybe even cut the budget of Bob Mueller and do something a little more stage crafty than the blunt instrument of firing the attorney general and trying to replace him."

If Whitaker takes over the Special Counsel investigation, he can simply do it himself.