America and fossil fuels
Stand back, I'm a geologist, this could get rocky (my coat? yes the one with the extra long sleeves that tie up at the back)...
America actually doesn't have a huge amount of oil. The USGS estimate, which is higher than almost anyone else's, puts proven US reserves at about 22 billion barrels (the precise number fluctuates depending on the price of petroleum) - about 2.5% of global reserves or 3.5 years of US consumption.
The potential for large new discoveries in the US is very low as the country has been thoroughly explored. There is some potential in very deep continental shelf traps and the very high Arctic, but it is always worth remembering that US oil production peaked in 1971 despite huge new production from fields under the North Slope and Gulf of Mexico.
Unconventional oil - shale and tar get more attractive as oil prices rise, but the US reserves of shale are predominantly in Colorado and Wyoming. They could be economically mined with current prices, but there is an insurmountable problem that one barrel of oil from shale needs three barrels of water - and the West is drying up as its water supplies are diverted to irrigation and the city. Shale is too bulky to transport for refining, so that problem seems to have no solution.
Hydrogenation of coal, yep it's a possibility, the new governor of Montana has said his state should become America's gas tank. Whether he could politically get the citizens of Big Sky country to accept the environmental cost is another matter. The same problem of water also applies - Montana has been in a two year drought now and much of the state is quite dry.
Finally, all reforming of hydrocarbons into synthetic crude produces enormous quantities of CO2. Even American politicians are starting to realise that global warming is a real problem and not a Hollywood plot gone wrong.