Not specifically liberal, I don't believe, although liberals are
generally running it up more (the general conservative line is that we
need to get more oil, instead). Problem is that we consume fantastic
amounts of energy as burned fossil fuels, and there is currently
nothing to replace them. Petroleum products as fuel for mobile
vehicles are hard to beat -- quite sage, high energy density, and the
combustion products are gases. Who wants clinkers falling (red hot)
out of the back of your car?
Biofuels are a hope, but with the current US farming methods, there is
some debate as to whether or not there is a net fuel gain -- I've been
hearing for at least 20 years that more BTU are consumed in production
of crops in the US that is present in the final product -- one must
include the energy costs of producing herbicides, pesticides, the
actual use of farm equipment, and the energy used to produce and
transport the fertilizers.
A knotty problem, not well addressed by anyone currently, certainly not
by advocating "hydrogen economies" as if the energy magically appeared.
Note that nuclear power is also not energy consumption free -- the
energy needed to produce the fuel for the reactors, and the BTUs
consumed to make all those cubic miles of concrete has to be added in
-- quite likely the net gain is small or negative. After all, there is
NO commercial nuclear fuel production to get numbers with. It's all
done by governments, and they all have good reasons to distort the
energy usage, if not downright lie about it.
Peter