Ukraine’s President Volodymyr Zelensky warned Tuesday that Russia’s just concluded “sham referendums” and attempts to annex Ukrainian territory rule out any talks with Moscow as long as Vladimir Putin remains president, and called for Russia’s “complete isolation” and tough new global sanctions. Speaking to the UN Security Council by video link over Russian objections, he urged additional military and financial support to defend Ukraine “so the aggressor would lose,” and “clear and legally binding guarantees of collective security” for his country in response to Russia’s latest grab for Ukrain…