Setting the stage for a congressional standoff, the U.S. House and Senate handed in opposite votes yesterday on a Pentagon-backed measure to ease endangered-species protections on military land. Four Republican senators broke with their party for a 51-48 vote against the measure, while the House supported it 252-175. Both houses of Congress are expected to pass their versions of a $400 billion defense spending bill today, but the environmental measure could be a sticking point in negotiating a compromise bill. Defense Secretary Donald Rumsfeld called the Senate vote “a mistake” and said he would try to reverse it. Rumsfeld also blamed environmental organizations for “aggressive litigation” that, he said, impedes military activity and could result in sending “men and women to battle without the training they need.” The Pentagon controls some 25 million acres of land that includes habitat for hundreds of imperiled species.