The Supreme Court struck down a federal law that restricts the president’s ability to fire members of the Federal Trade Commission, expanding presidential control over independent federal agencies. The court’s conservative majority voted 6-3 to uphold President Donald Trump’s decision to fire Rebecca Slaughter, a Democratic commissioner on the Federal Trade Commission who was removed from her position before her term ended.  The ruling overturns a unanimous 90-year-old decision known as Humphrey’s Executor that has limited when presidents can fire agencies’ board members — in part to try to ensure decision making free of political influence — or leave it with only its shell intact. The…