MAHMOUD Ahmadinejad — the Iranian leader Washington loves to hate — has only a few more months left in his presidential term. But this is not cause for celebration. If President Barack Obama really wants to improve relations with Tehran, working with Mr. Ahmadinejad may be his best bet. In a speech earlier this month commemorating the Islamic revolution’s anniversary, an event normally reserved for anti-American rhetoric, Mr. Ahmadinejad declared Iran’s readiness to talk to the United States. The election of a new president in June could slam shut a rare window of opportunity. Mr. Obama seems to understand this. He recently said that he will be looking for “openings” in the months ahead for face-to-face talks with Iran. President Nicolas Sarkozy of France cautioned that it would be wiser to hold off on talks until after the Iranian presidential elections. But this would be a bad idea.