Former Vice President Joe Biden today said he’s worried about the future of NATO, the alliance western countries formed after World War II to counter Russian aggression in Europe. President Trump has accused other allies of not paying enough to support NATO’s military operations.

“NATO is not a protection racket. NATO is essential to our long term security and has to be repaired,” Biden said today. “There’s much more to say, but I’ve probably said too much already.”

Biden told a crowd Ames he will have more to say on the subject tomorrow after the president returns to the United States. Trump has been in London this week, meeting with leaders from other NATO countries. Trump publicly rebuked France’s prime minister during a discussion about ISIS fighters and Trump called Canada’s prime minister “two-faced” after a video surfaced of the leaders of Canada, France and Great Britain talking about Trump’s impromptu news conference.