neither without a lot of investment on a scale like a mission to the moon type that they did in the 60's. When push comes to shove, the US will eventually move away from petroleum altogether. i don't think it will be in my lifetime however.
Yet, the "environment" is a hot potato during election time. Not that people make their mind on who to vote for because of it, but, since 80% or 90% of Americans say that they care about the subject, you don't want to get caught on the wrong side of it and have the rich environmental lobby spending even more $$ against you. Imo, the next administration, whichever of the two, will have to augment oil exploration, methanol, drilling, nuclear, wind, solar, research of all sorts, etc. We've been neglecting it for too long already