The "top kill" is underway, success uncertain. BP engineers are pumping mud at a furious rate into the damaged blowout preventer that sits on the uncapped well at the bottom of the Gulf of Mexico. The hazardous-but-high-reward maneuver comes five weeks into the oil spill crisis amid an intensifying atmosphere of political recrimination that has spread from the Gulf Coast to the White House and Congress. 
 
 The early bulletins on the top kill were encouraging. "The operation is proceeding as we planned it," BP chief executive Tony Hayward said Wednesday evening, adding that it would be 24 hours before BP knows if the well is dead. 
 
 The billowing plumes of effluent from cracks in the top of the riser pipe no longer look like oil and gas but have a distinctly muddy appearance. "What you've been observing out of the top of that riser is most likely mud. We can't fully confirm that because we can't sample it," BP Chief Operating Officer Doug Suttles said at a news conference Wednesday night. Speaking cautiously, he noted that if all goes as hoped, the well could be cemented shut by Thursday night. 
 
 President Obama, in a news conference Thursday, will outline tougher rules and regulations of the oil drilling industry and suspend exploratory drilling in the Arctic until at least next year, according to an administration official who spoke on condition of anonymity because the announcement had not been made. This will delay a controversial drilling effort by Shell this summer in the seas off northern Alaska. The moves come after a 30-day review of oil drilling that Obama ordered when the crisis began. 
 
 BP officials, having studied pressure readings, finally pulled the trigger on the top kill at 2 p.m. The world could follow the top kill via live video feeds from robots on the seafloor. It was strikingly similar to watching an Apollo moon landing: grainy images of unfamiliar technology in an alien landscape. 
 
 The procedure pumps heavy drilling mud from a ship on the surface down to the seafloor and into the five-story blowout preventer atop the well. If all goes as planned, the mud will slide about 2 1/2 miles down to the bottom of the well bore, rendering the well "static." Engineers would follow up with cement plugs to seal the well permanently. 
 
 Much could go wrong. The pressure of the injected mud could damage the blowout preventer and exacerbate the leaks. The mud will go wherever it can, and not necessarily where the engineers would prefer. 
 
 "There's a hole, but it's kind of like pushing toothpaste through an obstacle course," said Bruce Bullock, director of the Maguire Energy Institute at Southern Methodist University. 
 
 "I feel for the guys who are doing it, the people whose hands are actually on the throttles there," said energy analyst Byron King. "It's like doing brain surgery using robots under a mile of water with equipment that's got 30,000 horsepower of energy inside of it." 
 
 Millions of gallons of oil, and possibly tens of millions, have leaked into the gulf since the April 20 explosion and fire that killed 11 crew members on the drilling rig Deepwater Horizon, which sank two days later. 
 
 Oil has touched 84 miles of Louisiana's ragged shoreline and envelops the crow's foot of the Mississippi River delta. The oil trajectory forecast by the National Oceanic and Atmospheric Administration indicates that some of the oil has been captured by the gulf's Loop Current and by noon Friday could spread approximately as far south as, but considerably to the west of, Key West, Fla. 
 
 Traveling in Fremont, Calif., Obama said Wednesday that the passage of energy legislation has become more urgent because of the oil spill, which he called "just heartbreaking." Speaking to an audience of employees at a solar-panel manufacturing plant, Obama said the spill underscores the need to shift from fossil fuels to solar, wind and other types of power. He noted the great depth at which the Deepwater Horizon rig had drilled the now-leaking well. ||||| BP has agreed at the request of the Obama administration to show video of the "top kill" designed to choke off the oil spill in the Gulf of Mexico. 
 
 The company plans to try to execute the tricky procedure as early as dawn Wednesday. It's the latest attempt to plug the devastating oil leak. 
 
 The "top kill" involves force-feeding heavy drilling mud and cement onto the leak. 
 
 BP started showing live feed of the leak itself after pressure from the Obama administration. Lawmakers had said they had learned that the "top kill" procedure would not be shown. 
 
 The company said in a statement Tuesday that it will display the video. The decision came after discussions with the federal official overseeing the spill response, Coast Guard Adm. Thad Allen, BP said. 
 
 "Throughout the extended top kill procedure _ which may take up to two days to complete _ very significant changes in the appearance of the flows at the seabed may be expected," BP said. "These will not provide a reliable indicator of the overall progress, or success or failure, of the top kill operation as a whole. BP will report on the progress of the operation as appropriate and on its outcome when complete."
– BP has bowed to pressure from an increasingly ticked-off White House and reversed an earlier decision to cut off a live video feed as it attempts a top kill maneuver to plug the Gulf oil leak. The company—slammed by lawmakers yesterday after executives said the feed would be cut off during the attempt—warns that changes in the appearance of oil flow during the procedure may be misleading, the AP reports. The attempt to plug the leak with mud and cement was set to begin at dawn today and last up to two days. President Obama—who snapped "Plug the damn hole" at aides in a recent meeting, according to the Washington Post— has been receiving frequent updates on BP's progress. Top government scientists will be in the room with BP to supervise the attempt and consider alternatives if it fails.