Nobody knows yet all the circumstances and actions that caused the catastrophic April 20 blowout on the Deepwater Horizon drilling rig 52 miles from the Louisiana shore in the Gulf of Mexico, killing 11 workers.

Everything from criminal disregard for safety to lack of proper controls to simple equipment failure has been suggested. Gov. Rick Perry of Texas even called it an act of God.

No doubt, the earthly roots of this disaster will be known over time. Ongoing congressional investigations, governmental inquiries and even a detailed examination by a special presidential commission assure the world of that.

What's crucial now, other than stopping the massive flow of oil into the Gulf and cleaning as much of it as possible from beaches, bays, estuaries and even the deep water itself, is to properly determine how the tragedy will affect the future of U.S. deep-water drilling.

Some people want to stop offshore drilling entirely. With what the Interior Department says are more than 50,000 wells drilled in the Gulf of Mexico since 1947 and nearly 7,000 active leases, 64 percent of which are in waters deeper than 1,000 feet, a permanent halt is not likely.

What can and must happen is to make all drilling as safe as possible, revisiting regulatory requirements and procedures, particularly for the significantly higher risks in deep water.

That's what President Barack Obama ordered April 30, just days after the Deepwater Horizon exploded and later sank. The result of that order was a 30-day review led by Interior Secretary Ken Salazar that recommended a six-month moratorium — that Obama accepted — on all deep-water drilling and permitting while putting into effect new equipment, procedural and safety-training requirements.

Last week, a federal judge ruled against the moratorium. The Obama administration quickly said it would appeal that ruling. The administration also said it will consider a more flexible drilling ban.Some Gulf Coast residents, facing the very real fear of further economic damage to the region from a shutdown of drilling and drilling supply industries, want that moratorium lifted right away. So do some of Obama's vocal political critics.That would be a mistake. While blowouts and massive oil spills are relatively infrequent compared with the amount of drilling that goes on in the Gulf, the Deepwater Horizon proves that worst-case scenarios do happen.No major oil company, according to executives who testified in congressional hearings, is prepared to deal with that worst case and its environmentally devastating aftermath.One thing that is clear is that the Deepwater Horizon's blowout preventer failed at the most crucial time. That piece of equipment, sitting on the ocean floor almost a mile beneath the surface, was designed to seal off the well bore when a sudden surge of high-pressure oil, gas or water threatened to travel up or between the well casings and possibly cause the drilling rig to explode.Why it failed is unknown. Salazar ordered a complete reinspection of blowout preventers on the 33 active deep-water drilling operations in the Gulf and recertification that they meet regulatory requirements.The moratorium provides time to implement other worthwhile measures such as redundant shut-down mechanisms on blowout preventers, additional control systems, the capability to activate preventers with remotely operated vehicles and "dead man" emergency-activation systems.BP, the British company that operated the Deepwater Horizon, has dedicated $20 billion to paying for damages from the spill and a separate $100 million to compensate oil industry workers affected by the moratorium.The moratorium should end as soon as possible, but safety should come first.