At a very basic and general level, I think even most right-leaning economists would agree that some regulations are necessary, and actual improve the healthy functioning of a free market economy. A total laissez faire approach would only work if all costs were internalized by all economic actors. In the real world, that isn't the case. With no laws against it, a rational chemical firm will dump all their waste into a river because that is the cheapest way to dispose of it, and they don't have to internalize the costs (damages and destruction) created by these actions. This hypothetical firm will make inefficient decisions because they can't do an accurate cost-benefit analysis, underestimating and failing to internalize the costs of their actions. Good regulations seek to correct this problem, forcing firms to internalize all costs, and thus make more efficient decisions. Obviously, this is all pretty general stuff, but it's worth acknowledging that regulations are not all bad, and even hardcore free market people should accept that basic truth.
Most real world policy debates are more complicated than this, and raise questions of line drawing. I'm more liberal and will likely vote for Obama, but I can look at a state like California and see the terrible consequences of excessive regulation.
