The resources are there, we just need the will to utilize them. Coal to liquid fuels tech could fill a significant gap with diesel, kerosene and jet fuel applications. The primary issue is the volatile oil market which makes private investment risky, if the you have a situation like in late 2008 they are dead in the water because it costs more than conventional oil.
This tech will mostly likely emerge by itself but if you wanted to jump start it the only way your going to do that is to subsidize, what is interesting here is you don't need an all out subsidy but instead one that only kicks in if conventional oil goes below a threshold. This is one subsidy that could actually make economic sense because for the subsidy to kick in you would have had to succeeded in driving the cost of conventional oil down substantially which is your goal to begin with. You've also secured a source of oil inside our national borders, put US citizens to work etc.
There is other benefits as well, for example low quality coal can be used and it can also be used in a co-generation facility producing both liquid fuel and power.
This is a little dated but still applies for the most part:
Turning Coal into Liquid Fuel | NCPA