What is the British leader proposing regarding Ukraine and why is a US security guarantee considered essential?

The British leader is proposing to commit British ground forces in Ukraine alongside other nations if a lasting peace agreement can be established. This significant policy position reflects growing security concerns in Europe about Russian aggression. However, the leader emphasizes that a US security guarantee must serve as a backstop to this arrangement. This American involvement is described as the only effective deterrent against potential Russian attacks on Ukraine, underscoring the continued importance of US military support in European security frameworks despite anxieties about American commitment levels.