After a prolonged struggle between Democratic Party factions, the platform committee produced a statement of climate principles that its nominee could accept, and that its progressive activists could declare had at least moved the political needle in a greener direction.

Most notably, the platform that delegates will be asked to endorse at the Democratic Party convention, which starts on July 25 in Philadelphia, calls for putting a price on emissions of carbon dioxide and other greenhouse gases. It’s a formulation that stops short of an outright demand for a carbon tax, which Hillary Clinton has balked at.

Similarly, it emphasizes renewables over natural gas as the best way forward on clean energy, while stopping short of a ban on fracking.

And it calls for a climate change litmus test like the one President Obama used to block the Keystone XL tar sands pipeline—saying that federal decisions must “contribute to solving, not significantly exacerbating climate change”—but does not require that most fossil fuel reserves be left in the ground.

Even some activists who had wanted much more called this significant progress.

“The zeitgeist has shifted from ‘all of the above’ in 2012 to ‘keep it in the ground’ in 2016,” Jamie Henn, strategy and communications director for environmental activist organization 350.org, said in a statement.

The platform, which was contested more vigorously in last weekend’s platform committee meeting in Orlando than any in recent decades, is also more progressive than ever. It takes into account not just the concessions on climate but others on wages, trade, criminal justice and education. All these shifts moved Clinton in the direction of her primary opponent, Sen. Bernie Sanders, who finally endorsed Clinton after the platform issues were decided.

The party platform, however, is more philosophical position statement than binding policy directive.

The Clinton campaign has shown no indication that it intends to call for any form of direct pricing of carbon, such as a carbon tax or a national cap-and-trade system, efforts to address climate change that would require Congressional approval.

“Sec. Clinton would welcome working with Congress to address this issue but she also believes it is too important to wait for climate deniers to listen to science,” Trevor Houser, a Clinton campaign energy policy adviser said in a statement. “That’s why she is focused on a plan she can implement from Day 1.”

The divergence on climate policy disappointed environmentalists who had worked to forge a united platform between the Clinton and Sanders camps.

“We assume that everyone takes it seriously because it’s clearly been the vehicle for bringing together the Sanders and Clinton wings of the party, over very careful and detailed and elaborate bargaining,” said Bill McKibben, co-founder of 350.org, who helped draft the party’s platform. “One assumes they mean it, but if they don’t, every demonstration that we hold for four years will have those words written on the placards and banners,” McKibben said. 

Throughout her campaign, Clinton’s plan to address climate change has focused on redoubling existing regulatory measures like the Clean Power Plan, efforts that would not require Congressional approval. The centerpiece of President Obama’s climate policies, the plan has been stayed by the Supreme Court pending judicial review.

Policy analysts said this approach remains the best way to press forward given current political constraints that would make a direct price on carbon difficult to achieve.

“The opportunity cost in trying a strategy that would require Congress would just be enormous and we just don’t have that kind of time,” said Andrew Light, director of the Institute for Philosophy and Public Policy at George Mason University and a former climate official in the Obama administration.

Light said Clinton’s approach, which also calls for rapid growth in solar, is as ambitious as it is pragmatic.

“The top line on her renewable power plan, expanding solar energy to go from the 25-27 gigawatts we have right now in solar and get 140 gigawatts by 2020, that’s ambition,” Light said. “That’s about as ambitious as you could possibly imagine.”

Daniel Fiorino, director of the American University School of Public Affairs’ Center for Environmental Policy, prefers a carbon tax, but said it could cost the Democrats the election.

“I, like a lot of other people, think it’s the most elegant and direct solution to the problem to putting a price on carbon literally, but I think the word tax is seen as a liability and I think a lot of other Democrats, particularly senators in a variety of states would find that pretty heavy baggage to carry,” Fiorino said.

Clinton has consistently steered clear of advocating a tax on carbon.

“I want to do what we can do to actually make progress in dealing with the crisis,” she said at a Democratic Party presidential debate in April when asked by Sanders if she would support his call for a carbon tax. “And my approach I think is going to get us there faster without tying us up into political knots with a Congress that still would not support what you are proposing.”

The Clinton campaign’s focus on balancing environmental concerns with the pragmatism required to win an election was on display last weekend at the Democratic Platform Committee meeting when Houser spoke out against an amendment that would have called for a nationwide ban on fracking.

“My view is this, the same water pollution concerns, methane concerns, seismicity concerns that you all care about, I think that we can solve those without overnight cutting off two-thirds of all natural gas supply in this country, pushing us back to coal and threatening the livelihoods of millions of union households—many of whom also live in battleground states,” Houser said.

Fiorino said even a call for a national cap-and-trade plan, where power plants and other emitters can buy and sell permits to emit carbon dioxide or other greenhouse gases, would be labeled a tax by opponents. An unsuccessful bid for cap and trade by then-Reps. Henry Waxman (D-Calif.) and Edward Markey (D-Mass.) early in Obama’s first term was branded by conservatives as “cap and tax.” It passed the House but died in the Senate in 2010, before Democrats lost control of Congress.

“In terms of good environmental and economic policy both can make sense but it’s just so easy to distort that and turn it into a tax increase,” Fiorino said.

“If it’s perceived as a tax on carbon or tax on energy, that tends to be poorly received by the public,” said Dallas Burtraw, a senior fellow with Washington think tank Resources for The Future. “At the same time, poll after poll, the public will say that they are in favor of reducing carbon emission and that they prefer to see regulatory approaches.”

Burtraw said the Clinton campaign, whose climate advisers include John Podesta and Carol Browner, both veterans of her husband’s administration, still bear battle scars from a prior run at a carbon tax. In 1993, President Clinton proposed a “B.T.U. tax,” which would have taxed conventional energy sources. It failed and was seen as a factor in a number of Democratic legislators losing their seats in the 1994 midterm election.

“I think those scars are long-lived,” Burtraw said. “From a practical perspective, the Clinton campaign is saying she wants to pursue what she would see as a practical approach, something that can get it done without providing political dynamite.”

Regulatory measures, however, have their limits. The Clean Power Plan is limited in that it only regulates the electric power sector. (It would encourage states to use cap-and-trade approaches, a form of carbon pricing.)

“We are going to need to go deeper in the power sector and beyond the power sector, and the more we can take an economywide approach, the better able we will be to get the kind of ambition we need,” said Nathaniel Keohane, vice president of global climate at the Environmental Defense Fund.

Harnessing the Clean Power Plan and other existing regulations to rein in emissions would allow Clinton to address climate change without seeking Congressional approval for new measures. Pushing existing regulations beyond their current scope, however, has its own limitations.

“My big worry is that we probably now have done as much or more as we can with existing statutes,” said David Victor, co-director of the Laboratory on International Law and Regulation at the University of California, San Diego. “The more you take old laws and try and get them to do new tricks, the greater the risk that you are going to impose on the economy policies that are inflexible and much more expensive than necessary to get the job done.”

Clinton’s plan also calls for a $60 billion “Clean Energy Challenge” to fund solar and other clean energy projects. The source of the funding and timeframe are unclear.

“If that’s $60 billion per year of new money, that seems politically impossible,“ Victor said.

The Republican platform, meanwhile, is tacking to the right. After a unanimous vote on Monday, the Republican National Committee’s draft platform  declared coal “an abundant, clean, affordable, reliable domestic energy resource.”

Sanders highlighted the distinction between Clinton and Donald Trump in his endorsement of the Democratic Party’s presumptive nominee on Tuesday.

“Hillary Clinton is listening to the scientists who tell us that if we do not act boldly in the very near future there will be more drought, more floods, more acidification of the oceans, more rising sea levels,” Sanders said. “Donald Trump, well, like most Republicans, he chooses to reject science—something no presidential candidate should do. He believes that climate change is a hoax. In fact, he wants to expand the use of fossil fuel. That would be a disaster for our country and our planet.”