Senator Chuck Schumer delivered a pointed speech on the Senate floor excoriating Prime Minister Benjamin Netanyahu of Israel as a major obstacle to peace in the Middle East and calling for new leadership in Israel. But Mr. Schumer’s speech amounted to the sharpest critique yet from a senior American elected official — effectively urging Israelis to replace Mr. Netanyahu. He said the only solution to the decades-old conflict was a two-state solution: “a demilitarized Palestinian state living side by side with Israel