The Center for American Progress hosted Rep. Ed Markey at a roundtable for reporters to give a sort of primer for what to expect in the run-up to and during the marathon of international climate-change events in the coming week.

He was, to my ear, a little bit sanguine about the energy bill, which he expects will be completed and sent to the White House this fall, in time for the Congress to then turn its attention to a climate-change bill.

Markey said, “The NRDC estimates that that bill, if it was signed by the president, would meet 25 percent of the greenhouse-gas goals of the United States by 2030.” It’s unclear, though, whether he was talking about the NRDC’s ambitious benchmarks or the president’s laughably dubbed “aspirational goals” for long-term greenhouse-gas reduction. And in any case, it would depend upon all of the emissions-mitigating provisions of the bill — some now in the House version, some in the Senate version — finding their way into the final version that emerges from the conference committee.

I asked Markey about Rep. Rick Boucher’s dubious proposal to combine the energy bill with a climate-change bill, and he responded by pointing out the obvious objection: combining the bills would require holding up the energy bill for a year or more while the climate bill comes together, a wasted year during which the provisions of the energy bill could have been cutting the country’s carbon emissions.

I can think of a few other objections. First, there’s the veto issue: Bush is for now on the fence about the energy bill, but has long promised to veto any cap-and-trade climate bill. If the Democrats throw a cap-and-trade program into the energy bill, then they’ll surely lose both. If, on the other hand, they include weak climate provisions, Bush might give it a pass, but we’d then be stuck for years with an ineffective law while Congress turned its attention to other issues.

In an ideal world — with a Congress united behind fixing the problem and a president who wasn’t willing to sell out to industry — it might be helpful to build climate-change policy tools into an energy bill, because there’s so much overlap. Right now, for instance, Congress is all tied up arguing about CAFE standards in the energy bill. In a few months, though, they’ll have to decide whether to alter those standards within a climate bill and that could mean the same fight all over again. If they combined the bills, there’d be no redundancy.

But we go to war with the Congress and president we have, and as such it’d be foolish to try do it all at once.