Boris Johnson address to the nation following invasion of Ukraine

The transcript addresses the aggression of Vladimir Putin against Ukraine, emphasizing the need for this venture to fail. It appeals to the Russian people, questioning the actions done in their name, and expresses solidarity with Ukrainians, affirming that their national spirit will not be subdued. The speaker assures the British people and global allies of a united front to restore Ukraine's sovereignty, framing the crisis as an attack on democracy and freedom. The UK is committed to defending the right of European people to choose their future.

In what way does the speaker describe the aggression against Ukraine?

What fundamental right does the speaker emphasize regarding the sovereignty of European people?