Washington Post: THE SENATE is scheduled to vote today on a motion to proceed to debate on the Climate Security Act of 2008. Given this nation’s sluggish response to global warming, that will qualify as a big step. The chances of passage this year are worse than 50-50. But the markers being laid for the next president are worth pursuing. The world has clamored for U.S. leadership on climate change. Yet for seven years the Bush administration denied and dithered while the planet warmed. Initially, it …