THE BLUR of details and fog of ideological attacks can obscure the truly essential in the current congressional debate about legislation to confront global warming while building a green economy: the stark need for immediate action.

The bill recently unveiled by Senators John F. Kerry and Barbara Boxer represents an important step forward. The bill is not perfect, and ways that it can be strengthened are discussed below. However, it does include some of the most essential tools for addressing this most fundamental of challenges.

The Kerry-Boxer bill sets hard targets for greenhouse gas emission reductions consistent with the need identified by science. It creates new tools for tackling the job of climate stabilization while leaving in place the US Environmental Protection...