In a rare expression of a regret, President Donald Trump has admitted that he made a mistake by not visiting Arlington National Cemetery on the Monday after Veterans Day, a presidential tradition.

Why didn’t he go when he had the chance? According to a transcript of his conversation with Fox News Sunday anchor Chris Wallace from an interview set to air Sunday, he was “extremely busy” on Veterans Day.

Speaking with Wallace about his decision not to visit the Aisne-Marne American Cemetery in France on Saturday November 10 and Arlington Cemetery outside DC on Monday, Trump admitted “he wishes he had a rare do-over,” Wallace told Fox News’ Shepard Smith on Friday.

“I should have done that,” Trump said. “I was extremely busy on calls for the country, we did a lot of calling as you know.” (The president’s schedule for Monday November 12 was empty, at least of public events.)

“But this is Veterans Day,” Wallace pushed back, prompting Trump to admit he “could have” gone.

But, Trump said, he didn’t realize it would be such a big deal:

As you know I just left the day before the American Cemetery and I probably think — and that was one where it was raining as hard as you can imagine and I made a speech at the American Cemetery the day before. And I probably, you know, in retrospect, I should have. And I did last year, and I will virtually every year. But we had come in very late at night and I had just left, literally, the American Cemetery in Paris. And I really probably assumed that was fine and I was extremely busy because of affairs of state — doing other things.

Trump was widely criticized on Twitter and in the media for failing to visit and lay a wreath at the Tomb of the Unknown Soldier, with many asking “imagine if Obama had skipped Arlington.” Trump’s decision to forego the traditional visit came after he had already faced bipartisan criticism for backing out of a cemetery visit in France due to rain (Chief of Staff John Kelly went instead).

There were incorrect claims floating around that Trump was the first sitting president in 56 years not to visit Arlington on Veterans Day — in fact, presidents in recent years have often been overseas or at commemorations in different parts of the country, including Trump himself last year because he was in Vietnam for a Vietnam War commemoration. He was, however, the first ever to spend it inside the White House, tweeting about the vote count in Florida.