WASHINGTON, Sept 19 (Reuters) - Senate Republicans on Wednesday blocked a Democratic plan to give U.S. troops in Iraq at least as much rest time at home as they spend deployed abroad. The measure needed 60 votes to pass in the Democratic-controlled Senate; it received just 56, with 44 voting against. The proposal drew intense opposition from the Bush administration, which saw it as a backdoor attempt to pull troops off the battlefield in the increasingly unpopular war. The outcome marked another defeat for Democrats on legislation widely considered their best near-term chance to change the current Iraq strategy.