Guardian editorial: The Kremlin has barely lifted a finger in recent days. It hasn't needed to. The 28-point US-Russia peace proposal, leaked to the media last week, has thrown Washington, Kyiv and European capitals into disarray, creating precisely the conditions Vladimir Putin has long sought: a negotiating table sharply tilted in the Russian president's favour, with Ukraine cornered into weighing terms it cannot accept and the threat of losing its most important ally hanging over its head.