John Bolton, Trump's former National Security Advisor, stated that sitting in the Oval Office he heard Trump state in a phone all to Putin that if he was reelected in 2020, his first act of his new term would be to withdraw the US from NATO, so Putin could then invade Ukraine with no worry of any NATO opposition. For Biden to unify NATO in support of Ukraine that quickly after Russian's invasion was an amazing accomplishment which probably only Biden known to Europe from his decades of foreign policy experience could have pulled off. Zelenskyy recognized this by addressing Biden both as "President of the United States" and "Leader of NATO's Support of Ukraine".