President Trump fired off rare public criticism of Russian leader Vladimir Putin and sat for a dramatic one-on-one talk with Ukrainian President Volodymyr Zelensky in the Vatican over the weekend,

Zelensky used the funeral of Pope Francis to launch a diplomatic blitz to head off a U.S. proposal to end Russia’s war on Ukraine on terms favorable to Moscow.

US Secretary of State Marco Rubio has warned that imposing new sanctions on Russia could extend the Ukraine conflict by two more years. Speaking on NBC’s Meet the Press, Rubio emphasized the critical diplomatic window the US is currently navigating.