The big picture: There are several forces behind this open landscape, including...

• There's pent-up interest among House Democrats, but leadership is not necessarily in-step with the insurgent progressives. Speaker Nancy Pelosi's lukewarm response to Rep. Alexandria Ocasio-Cortez's Green New Deal (GND) demonstrates that tension.
• The big Democratic primary field lacks a clear front-runner, so in effect there will be a bunch of boutique policy shops operating separately that will seek to create ideas that stand out.
• There's a new set of policy think tanks and advocacy groups backing the party's insurgent left flank.

Where it stands: With Washington largely stuck until at least after the 2020 election, there are lots of wonky efforts to shape policies that would be ready for launch if...

• Democrats regain the White House and the Senate (but even then, Senate rules create massive hurdles).
• The stars somehow align for a climate deal that can attract a small but critical mass of Senate Republicans.

What we're hearing: Advice is flying in from all angles...

1. Joseph Aldy, a former Obama aide now at Harvard, states in The Conversation that the 2009 stimulus — the big green investment vehicle of its time — holds lessons for the GND.

2. Ramez Naam writes a lengthy piece for TechCrunch that looks at what Democrats could push without a filibuster-proof majority (which they're highly unlikely to have). Killing the filibuster would open more options but the appetite is highly uncertain.

3. Martin Wolf explains in the Financial Times why a carbon tax, which lots of economists like, won't be nearly enough.

• Wolf sees space for linking it to some ideas in the GND, which he also finds incomplete. "The Green New Deal recognises the need for regulatory intervention and infrastructure investment. Unfortunately, it places no weight on incentives at all," Wolf writes.
• Quick take: Expect to hear more of this discussion. While it's true that taxes have buy-in from a handful of Republicans, a carbon price would probably have to be extremely high — untenably high — to yield very steep emissions cuts.
• As the UN science panel's big report last year noted, "While an explicit carbon pricing mechanism is central to prompt mitigation scenarios compatible with 1.5°C pathways, a complementary mix of stringent policies is required."
• But the politics here are daunting, because conservatives pushing carbon taxes see them largely replacing regulations and mandates.

Escalating trade wars could limit America's rise as an oil and natural gas exporter while further boosting renewable energy use in some countries, BP's latest long-term energy outlook finds.

Why it matters: Surging shale production — combined with growing LNG and crude export infrastructure — is making the U.S. a player in global export markets. The Energy Department sees the U.S. becoming a net exporter in 2020.

But, but, but: BP's report, which is part of its annual, wide-angle look at the global energy system over the next 3 decades, models a scenario in which global trade disputes persist and worsen.

• That would slow global GDP and energy demand growth, with the effect "concentrated in countries and regions most exposed to foreign trade."
• "The risk premia on imported energy means the fall in energy consumed is concentrated in traded fuels (oil, gas and coal), with renewable energy increasing slightly."

What they did: BP's report contrasts this "less globalization" scenario with their "evolving transitions" (ET) case, which sees national policies, tech development and other forces continuing in a way that's consistent with the recent past.

What they found: Russia's exports are crimped, but the effect on the U.S. is even greater. "By 2040, US oil and gas exports in the ‘Less globalization’ scenario are around two-thirds lower than in the ET scenario."

The intrigue: Greater protectionism would slow down U.S. demand growth for renewables compared to the ET scenario as the country uses more of its domestically produced fossil fuels.

• However, that's more than offset by greater EU and Chinese renewables demand growth relative to the ET case.

Go deeper:

• Read the report.
• Carbon Brief compares this year's report to prior versions.
• The Wall Street Journal explores the top-level findings.

Sen. Amy Klobuchar said at a CNN town hall in New Hampshire last night, "The Green New Deal is so important right now for our country. We may not have agreements on exactly how it will work and when we can get it done."

• She cited data showing last year was the 4th warmest on record, pointed to extreme weather events, and talked up jobs in low-carbon industries.

Sen. Kamala Harris said at a weekend New Hampshire event that climate change is an "existential threat."

• "We have to have goals. It's a resolution that requires us to have goals and think about what we can achieve and put metrics on it," she said, via C-SPAN.
• "Some of them we will achieve and some of them we won't," Harris added. "But if we don't aspire, this is going to be a bad ending."

Sen. Cory Booker, in a recent interview with an Iowa NBC affiliate, compared the climate challenge to the moonshot.

• "Now is the time we do need bold, visionary leaders," Booker said, but added: "I am a former mayor. There is no more of a pragmatist than me about solving problems, and when you get everybody around a table to negotiate, you don't get everything that you want all the time."

The big picture: Republicans see a political opening in the plan — which is co-sponsored by nearly a half-dozen candidates — and its troubled rollout earlier this month.

• Senate Majority Leader Mitch McConnell is planning to bring up the resolution for a floor vote, although the timing isn't clear.

Go deeper: Alexandria Ocasio-Cortez's Green New Deal gets first fight in Senate