... Without that juicy legislation by Congress, they would have been damn sure their stuff was safe, because they would be on the hook for the entire damages otherwise...
Right. BP's corporate misfeasance is Congresses fault, because we know corporation always act in an optimal way to preserve their long-term self-interest and would never cut corners otherwise to risk horribly expensive disasters.
Let's look at something that BP was responsible for less than four years ago: the Alaska oil pipeline shutdown (http://www.msnbc.msn.com/id/14219844/).
Set aside the environmental aspects of the spill entirely and just focus on how BP managed that pipeline which delivered 8% of U.S. oil consumption and $30 million of revenue a day. Obviously in possession of such a cash cow, BP's enlightened self-interest ensured that they would keep that pipeline in good condition so that that billion-dollar-a-month gusher would never dry up. But did they? Nooo... they cut corners on maintenance and suffered an entirely avoidable shutdown.
The Libertarian notion, taken up by many non-Libertarian right wingers also -- that regulation is unnecessary since the discipline of the marketplace guarantees good corporate behavior and citizenship (And maximizes economic performance in the short and long terms! Really, no downside at all it seems!) -- is a quaint bit of Nineteenth Century economic utopianism.
Although pointing in a different direction, this "perfect free market" notion is strikingly similar to the character of Marxist thought - another bit of economic fantasy literature harkening back to the 1800s. Both are elegant theoretical structures, so pleasing to its adherents, that the naked evidence of its disastrous failures (and thus the falsity of their premises) in the real world go entirely unacknowledged.