Moderator Kristen Welker asked Johnson what he thought about comments by Sen. Lindsey Graham—a once staunch supporter of Ukraine on the Republican side—in which he said that for Ukraine-Russia peace agreements to occur, Zelensky may need to resign.

Ukrainian President Volodymyr Zelenskyy met with British Prime Minister Keir Starmer one day after a meeting with President Donald Trump that ended with questions about Ukraine-U.S. relations. NBC News' Megan Fitzgerald reports on how Europe may need to step up and defend Ukraine against another Russia invasion without the aid of the U.

UK Prime Minister Keir Starmer on Saturday gave Volodymyr Zelensky a warm welcome in London, a day after the Ukrainian leader's clash with US President Donald Trump.

British Prime Minister Keir Starmer on March 2 said Europe was “doubling down” on Ukraine support and called the U.S. a "reliable ally."

"We are at a crossroads in history today," Starmer said after a summit of 18 leaders - mostly from Europe and including Ukrainian President Volodymyr Zelensky, who said Ukraine felt "strong support" and the summit showed "European unity at an extremely high level not seen for a long time".

"We stand with Ukraine for as long as it may take," U.K. Prime Minister Keir Starmer told reporters at a press briefing on March 1 in London alongside President Volodymyr Zelensky, adding that Ukraine has "full backing across the United Kingdom.