After several years of near silence on the problem of climate change, President Obama finally gave a major speech last month on how the United States would address this looming global problem.

That he did so is notable. But the new U.S. plan is, for the most part, the same as the old plan. It includes dozens of efforts, most of them already in place, to boost efficiency, switch from high-emission fuels like coal to cleaner natural gas, and promote new ultra-low emission technologies. Discussion by analysts, lobbyists, and policy makers over the impact of the details on emissions and the economy has already begun. Yet so far practically nobody is talking about the single most important test for Obama’s plan: international leverage.

In 1990, when global warming first rose to prominence as an international issue, the U.S. was undisputed as leader of the global economy and the world’s biggest polluter. Since then, the U.S. share of all the different gases that cause global warming has dropped from 16 percent to 13 percent and is poised to decline further. U.S. emissions have been roughly flat since the late 1990s and are now falling while the rest of the world, notably China, has grown rapidly. In 1990, the U.S. couldn’t stop global warming on its own, but it could unilaterally set the tone for the world. That never happened, and today the global problem is much bigger and harder to manage.

The key question is whether a new U.S. national policy will have any impact on other countries. So far, the answer is probably no. U.S. credibility in international global warming diplomacy has suffered because the U.S. is seen as good at criticizing what it doesn’t like in the various schemes to cut global emissions, such as the Kyoto Protocol, but not very talented at creating alternatives that actually work.

Other countries now understand that political gridlock in Washington makes it hard for American diplomats to promise much to the rest of the world. It is unlikely that any global treaty for cutting emissions would get the needed legislative approvals from Congress. It is telling that the new climate plan outlined by President Obama relied mainly on regulatory and funding actions he can take alone, rather than new legislation that would require help from Congress.

But while U.S. leverage on international, Kyoto-style negotiations looks weak, there are interesting glimmers of hope. In recent months the Obama administration has reinvigorated efforts to cooperate directly with China on programs to study and test low-emission energy technologies. At the Sunnylands summit in June, the leaders of the two countries also agreed to help phase out hydrofluorocarbons (HFCs), potent global warming gases that are relatively easy to tame.

Piecemeal efforts to work with countries individually or in small groups are now likely to be more effective for the U.S. than big global forums on climate action. Because these smaller forums make it easier to focus and achieve action, they are probably also the best way for other countries to find practical ways to cooperate.

Closer to home, the most immediate evidence of international leverage could come from Canada. The Keystone XL pipeline that would move oil from the Canadian oil sands to lucrative markets may provide the first concrete success. Its fate is in U.S. hands, and while oil sands would simply travel by alternate routes without it, holding back approval could force the Canadians to promise their own more credible program to cut emissions. 

Because emissions anywhere affect the whole planet, every plan from those of the smallest cities to those of the biggest nations should be judged by whether they advance the global agenda. On that score, Obama’s new climate plan could signal a fresh start—if it gives the U.S. more practical leverage on the actions of other countries as well as here at home.

David G. Victor is a professor at the School of International Relations and Pacific Studies at the University of California, San Diego, where he leads a group studying the effectiveness of international law. He is the author of the 2011 book Global Warming Gridlock: Creating More Effective Strategies for Protecting the Planet.