One cheer for Senator Kevin De León.

The leader of the State Senate introduced legislation yesterday adding comprehensive new regulations to control California greenhouse gas emissions.

No, I’m not endorsing the substance of his legislation. More on that below. But the Senator deserves credit, along with other Senate and Assembly leaders, for insisting the Legislature play a leading role in what the state’s new policy should be after the expiration of AB 32 in 2020.

After all, the California Global Warming Solutions Act of 2006 comprised less than a dozen pages of statute – less than half of what it would take to regulate interior decorators. AB 32 was long on legislative intent and aspiration, but brief on specific direction and policy. It left all the dirty work and most of the controversy to the Air Resources Board, which over the course of two administrations has developed a  regulatory scheme that touches every corner of the California economy.

The mandates of AB 32 extend only through 2020. The good news is that Senator De León, following separate efforts by Senator Fran Pavley and Assemblyman Henry Perea, has staked a claim that the Legislature should play a key role in developing California’s climate change policy for the decades after 2020.

There is little question that California will adopt just such a policy. In his inaugural address last month, Gov. Brown touted the state’s “most far-reaching environmental laws of any state and the most integrated policy to deal with climate change of any political jurisdiction in the Western Hemisphere.” The Governor went on to state the case for even further GHG emission reductions, reiterating that “reducing carbon is compatible with an abundant economy and human well-being.”

Just how to incentivize or engineer these reductions will be the central battleground of the post-2020 debate. The Governor gave some examples of how California might meet a 2030 benchmark, but stated them as “ambitious goals,” not policy prescriptions.

Sen. De León takes a different approach – turning the Governor’s aspirations into policy prescriptions.

Without so much as a wink toward market mechanisms, the Pro Tem’s approach is determinedly command-and-control:

This proposal by the Senate leadership is an important milestone in the 2015 climate change policy debate. Along with the plan to be rolled out by the Brown Administration, and additional regulatory or market approaches surfaced by others, the Legislature should have a full range of options to consider.