Senate Republicans on Wednesday narrowly blocked the strongest congressional effort yet to force an end to the war with Iran , as three Republican senators broke with their party over President Donald Trump’s handling of the conflict. The measure, brought under the 1973 War Powers Resolution, failed by a single vote, 50 to 49. It was the seventh attempt in the Senate to pass such a measure since the war began in late February, and the first time Senator Lisa Murkowski, Republican of Alaska, voted for it.  Murkowski was joined by Republicans Susan Collins of Maine and Rand Paul of Kentucky in backing the resolution. Collins first broke with Republican leadership on the issue last month, shortly before the expiration of a 60-day legal window that some legal experts argue required the Administration to seek congressional authorization for continued military action. Paul, a longtime critic of expansive presidential war powers, has voted for all seven attempts.…