At each step of the way, the actions that have angered Trump have been steps taken by senior officials specifically following the law. In a shocking turn of phrase, even by his standards, Trump said, “So I just heard they broke into the office of one of my personal attorneys.” Of course, “they” didn’t “break in”—they obtained a search warrant: sought by the U.S. Attorney, with the sign-off of the deputy attorney general, and approved by a magistrate judge. “They” means the FBI, part of Trump’s own executive branch, acting according to the law.
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This idea, that there is a regimented process for charging people and that it ought not to be determined by political vendettas or the whims of the head of government, is central to the American project, even if the nation has at times fallen short of it. Trump has long struggled to understand and accept the idea of the rule of law. On the campaign trail, he promised to lock Hillary Clinton up and questioned the right of a federal judge to oversee a case involving Trump University. Monday’s comments, including his stunning equation of a legal warrant with a burglary, are the clearest demonstration that Trump is engaged not just in a political attack, but in a campaign against the rule of law, and the U.S. approach to justice, itself.
Nifty detail: Mueller's team did not do this. SDNY did.
Presumably meaning unconfirmed Trump interim US Attorney Geoffrey Berman approved it.