Fracking, or hydraulic fracturing, is a technique that significantly increases production from oil & gas wells. Particularly in cases with a poorly permeable reservoir & where the pressure difference between the reservoir and the well bore is low. In those cases production can drop below the economic cut-off long before the reservoir is properly drained. By hydraulically creating fractures in that reservoir, production greatly increases, and recovery from the reservoir is enhanced. Because of its geological and environmental setting, the US has greatly benefited from this technique:
The result of this technological development is a reduction in oil imports, cheap fuel for manufacturing, and lower costs to the consumer (estimated at an additional disposable income of $1200/y per household). All this brings massive benefits to the economy.
Just pointing out that the revival now seen is not the result of one man, or political position, or party, but instead a continuation of something that started earlier, and which is purely based on a technological development that happens to be very suitable for the US setting.