It was the gaffe heard around a world that is closely watching signs that President Joe Biden’s age could become a deciding factor in who leads the United States — and helms the powerful nation’s foreign policy.

Biden’s comment during his closing remarks at the NATO summit in Washington appeared to confuse Ukrainian President Volodymyr Zelenskyy with Russian President Vladimir Putin.

“Ladies and gentlemen,” Biden said as he introduced Zelenskyy, “President Putin.”