Environment News Service: U.S. Senator John McCain, the presumptive Republican nominee for president, today announced that he has selected Alaska Governor Sarah Palin to be his running mate and to serve as his vice president. His choice puts the twin issues of energy and environment at the center of the 2008 election campaign. “Governor Palin is a tough executive who has demonstrated during her time in office that she is ready to be president,” McCain said today in Dayton. “Governor Palin has challenged …