Why is diplomacy essential for resolving the Ukraine conflict?

According to Dr. Sergei Markov, it is impossible to transition from war to peace without diplomacy. He argues that Western countries not only acted as aggressors by overthrowing Ukraine's democratically elected president in 2014 and imposing what he calls an illegal regime, but they have also blocked diplomatic efforts to resolve the conflict. Markov claims this diplomatic blockade made peace negotiations impossible before Donald Trump's potential return to power. He presents diplomacy as the crucial missing element in resolving the Ukraine conflict, suggesting that genuine diplomatic engagement is necessary to move beyond the current state of war toward a peaceful resolution.