Testing the limits of presidential power, Donald Trump this week tightened his grip on U.S. government agencies that for years have taken pride in their independence overseeing such matters as elections,

White House seeks sway over FCC, FEC, FTC and some Fed operations. Politics professor Sarah Binder says it "grabs power from Congress."

The executive order would affect agencies like the SEC and FDIC, but it excludes the Federal Reserve's Board of Governors and Open Market Committee.