Rubio comes a long way to become most dominant US diplomat since Kissinger

Secretary of state will take on dual role as national security adviser - and just like half a century ago, times are turbulent

Marco Rubio, you have come a long way.

From being ridiculed as Little Marco" by Donald Trump during the 2016 Republican primaries, the former Florida senator now stands - on paper, at least - as the US's most powerful diplomat since Henry Kissinger half a century ago after his former nemesis appointed him acting national security adviser to replace the departing Mike Waltz.