^ "An indictment - a formal accusation that someone has committed a crime - can be brought only by a prosecutor working either in the federal or state system. Mr. Mueller is one such prosecutor. But even if Mr. Mueller has the goods on Mr. Trump, two barriers remain before he may indict him. First, some constitutional scholars believe a sitting president cannot be indicted. And second, two Department of Justice opinions, dating back to the Nixon and Clinton administrations, side with this view."

From this nytimes opinion piece written by someone who I have no idea who he is: https://www.nytimes.com/2018/05/21/opinion/neal-katyal-indict-trump.html

Anyway, none of this matters since Trump hasn't committed any crimes, especially with anything to do with Russia. Plus collusion isn't even a crime, as I have mentioned before.