People are constantly asking me, “Is the climate bill going to pass?” The answer is: I don’t know. No one knows. Confident predictions either way are mostly posing. The situation, like so much in politics right now, is incredibly fluid.

There are five things to watch in coming months that will give us a better sense of how the bill might fare.

1. The Murkowski resolution

On Thursday, Sen. Lisa Murkowski (R-Alaska) will introduce a “resolution of disapproval” that would short-circuit EPA’s ability to regulate carbon pollution. By the mysterious alchemy of Beltway media, the vote has become a bellwether for the climate bill’s chances.

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Murkowski’s resolution is filed under the authority of the Congressional Review Act, a rarely used law that allows Congress to overturn the actions of an executive branch agency. (It’s only been used successfully once, to overturn some Clinton-era ergonomics regulations in 2001.) It would reverse EPA’s “endangerment finding,” the key legal document that establishes the agency’s obligation to regulate greenhouse gases as air pollutants under the Clean Air Act.

Whatever Murkowski says — and her rhetoric behind this has been an exercise is grotesque bad faith — the resolution is entirely nihilistic. All the endangerment finding says is that climate change is a danger to public health. To protest that finding is to protest climate change science.

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If passed, the resolution would wreak havoc on the vehicle fuel-economy standards worked out between the EPA, California, and auto companies (and the standards under discussion for 2017 forward). It would also disrupt the very legislative efforts Murkowski claims to support. The cap-and-trade system in the climate bill is run by the EPA, as a title under the Clean Air Act; how can that be legally kosher if the EPA is forbidden from judging greenhouse gases a danger?

But of course it won’t pass; nobody, Murkowski included, thinks it has a chance. If it got through the Senate, it wouldn’t get through the House; if it got through the House, Obama would veto it. It’s an act of pure grandstanding on Murkowski’s part.

But pundits have decided that the vote is an indicator of support for the climate change bill. The resolution needs 51 votes, to pass. If it breaks 45 votes, it’s trouble. If it breaks 50, it’s doom.

2. Committee chairs

Last Thursday, Senate Majority Leader Harry Reid (D) notified Senate committee chairs that he plans on moving a comprehensive energy bill in July. He asked them to prepare ideas, specifically ideas to address the BP Gulf oil disaster. Receiving letters were Max Baucus (Finance), Jeff Bingaman (Energy), Barbara Boxer (Environment), Chris Dodd (Banking), Patrick Leahy (Judiciary), Joe Lieberman (Homeland Security), Blanche Lincoln (Agriculture), and John Rockefeller (Intelligence). (Weirdly, at least according to Politico, Kerry himself, chair of Foreign Relations, didn’t receive one.)

Reid pointedly did not say whether he planned to model his legislation on the Kerry-Lieberman American Power Act or whether it would contain a carbon cap or carbon-pricing system at all. He’s trying to get the lay of the land so he can put together a bill that can pass. Much will depend on what the chairfolk tell him. In particular, what he hears from Bingaman (who has been stumping for an energy-only bill) and Baucus (who has been conspicuously quiet on the subject) will have an outsized effect. They are pivotal Movers of Moderates.

3. Lugar’s bill

Today, Sen. Richard Lugar (R-Ind.) will introduce his own energy legislation, which does not contain a cap-and-trade system. If it becomes clear that carbon pricing doesn’t have the votes this year, it could serve as a “bipartisan” model for Reid to fall back on.

While it’s clear a carbon cap is crucial to the long-term success of a climate-change mitigation program, Lugar’s bill is actually a fairly decent fallback — as good or better than the energy bill that came out of Bingaman’s committee last year. To quote myself:

[Lugar’s] plan is admirable for its simplicity and the clarity of its goals: capturing energy efficiency, diversifying and cleaning up the electricity sector, and reducing foreign oil dependence. Each of those goals is served by a range of policy instruments, from building efficiency standards to loan guarantees for clean energy generators to higher CAFE standards.

We’ll see what reaction, if any, the bill gets upon its official debut.

4. Oil spill

BP seems to have had some modest success in getting a cap in place, siphoning off about 10,000 barrels a day of the 20,000 (or so — nobody knows for sure) gushing into the Gulf. But that’s probably the last good news until at least August, when BP thinks it can have the relief wells drilled.

Until then the spill will be in the news, yielding more and more pictures of oil-choked wildlife. Oil’s going to be coming up on more and more beaches, including in Florida, and in the background hovers the unthinkable prospect of a hurricane that could carry crude oil miles into the fragile Gulf coastal marshes and wetlands.

How will this drip-drip horror affect the public’s appetite for comprehensive climate and energy legislation? On one hand, it seems inevitable that support for offshore drilling will continue to decline. In a Friday CBS poll, a majority opposed expanded offshore drilling for the first time. Time will tell how much that anger translates into ambition to escape oil, but clearly the anger is rising.

On the other hand, every day the spill goes on Obama looks more and more helpless and the federal government looks more and more hapless. If the public is disgusted by the feds’ performance, will it be keen to let the feds pass a massive, far-reaching piece of legislation?

5. Obama

What will Obama do in the face of public anger over the spill? His attempt at keeping his distance and muting talk of energy policy obviously hasn’t worked. He’s figured out he needs some kind of positive, muscular response, and since he can’t pilot a Federal Super Submarine down into the Gulf and fire lasers at the spill, legislation is about the best option on the table. In his speech last week, he came out far more strongly behind the climate/energy bill than he has previously, saying “I intend to find” the votes and “we will get it done.”

Will he follow up on that promise with the same kind of full-court press he put behind the health-care reform bill? A senior administration official told Politico, “It’s the next big thing.” We’ll see.