Because antidevelopment environmentalists know how to manipulate fear, advocates of oil and gas development need to know how to combat it. Fear and its environmentalist promoters are impeding development of the huge Marcellus shale gas resource in New York and Pennsylvania.Opponents to drilling have raised fear about hydraulic fracturing, the technique that has been used safely and often since the 1940s, modern refinements to which make shale development possible.But use of hydraulic fracing is new to parts of Pennsylvania and New York, and drilling opponents say it threatens subsurface drinking-water supplies.Gas operators and industry associations have made commendable efforts to educat...