Drew Brandewie: Chief of staff, Sen. John Cornyn (R-Texas)

Sen. John Cornyn (R-Texas) has worn many hats during his two-plus decade tenure in the upper chamber — and chief of staff Drew Brandewie has been with him for much of that time. Cornyn has run the Senate GOP’s whip operation, the National Republican Senatorial Committee (twice) and has been a key ally of Senate…