One of the people we’ll be hearing from on today’s programme is Estonia’s Prime Minister Kaja Kallas.
She has told the BBC that leaders risk ignoring lessons from the 1930s and 1940s if they do not bolster support for Ukraine.
In a striking warning, Kallas has said that war could expand “very fast in Europe, so no country is left untouched” if Vladimir Putin wins.
The leader of Estonia, which borders Russia, called on Ukraine’s allies to “do the utmost to help”.
Kallas has also urged Nato countries to increase their defence spending.
Currently, Nato members are asked to contribute 2% of their GDP to defence.
Kallas wants Nato countries to increase defence spending to 3% of their GDP.
Stick with us to follow Kaja Kallas being interviewed by Laura Kuenssberg later on the programme.