Is the "Perfect" the enemy of the "Good?"

The Lieberman-Warner "Environmental Sell-out to Polluters" bill got through its first markup in committee yesterday. Kate Shepard on Tapped:

Yesterday afternoon, John Kerry held a conference call with bloggers that covered a range of topics, from international accords to probably the hottest domestic topic, the Lieberman-Warner bill, or "America's Climate Security Act."...Kerry seemed to think that worries about passing weaker legislation now and getting stuck with it are unfounded. We can pass a plan now and strengthen it later, he says, as support for action on climate change grows among citizens and businessfolk

.Just out of curiosity, can somebody provide examples of bills--legislation, yaknow?-- which were regarded as too weak at their passage, and which were subsequently STRENGTHENED in the public interest--that is, their regulatory properties were INCREASED--later at the expense of the interests which assured their weakness in the first place?