The idea that a country can’t increase the size of its territory by taking it over another has been a principle of Western foreign policy for decades. If that changes it will be a profound shift.

“Once that genie’s out of the bottle, it will be very hard to put back in”, says Tom Wright, the Irishman who was a member of Joe Biden’s National Security Council and is now a senior fellow at the Brookings Institution, a foreign policy think-tank.

Wright, who was involved in the formation of Biden’s policy on Ukraine, talks to Hugh Linehan about foreign policy under Biden and Trump on today’s Inside Politics podcast.