With Joe Biden as president, the United States is certain to rejoin the international community in the Paris climate accord. Much less certain is whether the United States is capable of being a reliable long-term partner. Several moving parts are still in play.

Biden’s campaign included ambitious plans to confront global warming and lead the U.S. to a net-zero carbon economy by mid-century. However, it will take more than a supportive president for the United States to stop polluting the atmosphere. The other two branches of the government, Congress and the courts, must be supportive, too.

Some history may be helpful. Several years ago, the Republican Party decided to make climate change a political issue that would drive a wedge between the two political parties and their voters. Republicans in Congress who once acknowledged the climate crisis fell silent and began voting against any proposal to address it. Congress has not taken any significant action against global warming since the U.S. Senate voted in 1992 to ratify the United Nations Framework Convention on Climate Change.

When it became clear that Republicans intended to reject any solutions Obama proposed, he resorted to using his powers as president to issue directives and rules. For example, the U.S. government is one of the world’s biggest fossil-fuel consumers, so Obama ordered agencies to become energy efficient and to use renewable energy technologies. His administration issued rules to limit carbon dioxide emissions from power plants and to establish tough new fuel-economy standards for trucks and cars.

But while laws are relatively permanent, presidential directives are not. Each president’s actions can be undone by his or her successors. When Donald Trump became president, he methodically reversed Obama’s progress, including America’s participation in the Paris accord.

What can we expect when Biden takes over as president on January 20? He wants to make massive investments in zero-carbon energy and to restore many of the policies and programs that Trump trashed. But if Biden wants new laws and sufficient budgets, another hyper-partisan Republican Senate may block him. That will be decided in January when voters in Georgia elect two Senators. If Democrats win both elections, the partisan split in the Senate would be 50-50. But Democrats would have an edge. Under the Constitution, the Vice President, in this case, Democrat Kamala Harris, presides over the Senate and can use her vote to break ties. If Democrats do not win both seats, Republicans will keep control of the Senate.

Other scenarios are possible:

  • Biden, who served in the Senate for 36 years, still has friends there in both political parties. He knows how to reach deals with Senators who disagree with him. He could use that skill to win some concessions on climate legislation.
  • Not all Republicans in Congress reject the reality of global warming, but they have been afraid to contradict Donald Trump. With Trump out of the way, they may feel free to join Democrats in supporting reasonable climate legislation like a price on carbon.
  • Public pressure for government leadership could grow to the point that Republicans in Congress believe it would be politically stupid to continue opposing climate action. Polling shows that 72% of American adults now accept that global warming is real, and 60% want the president and Congress to do something about it. As the election year began, however, only 25% of Republicans considered climate action a top priority for Congress and the president.
  • More grassroots Republican voters could support federal action if their party leaders do. There is a complicated reciprocal relationship between political leaders and the American people. Studies show that citizens tend to follow their leaders on issues, especially when they are complicated like climate change. As if to confirm this, Biden’s strong support for climate action and Trump’s complete denial are reflected in the polls I just cited.

Whatever scenario unfolds, the Biden Administration will work to restore the most important of the more than 100 environmental regulations that Trump weakened or repealed during his presidency. Many of them would reduce the greenhouse gas emissions responsible for global warming, including tougher efficiency standards for vehicles and limits on CO2 pollution from power plants.

Progressives on the left will continue pushing Biden for more aggressive leadership including the Green New Deal. However, rather than fighting Republican accusations that the Green New Deal is socialism, Biden could champion a new green ideal where environmental stewardship and climate stabilization are baked routinely into every relevant federal policy, from infrastructure modernization to air quality and public health, and from job creation to energy security. Biden already is committed to the Green New Deal’s goals for economic, environmental and social justice. The Deal’s energy goals would find their paths of least resistance if they are integrated with job creation and other federal programs.

Finally, Biden and his team cannot let themselves be distracted from the climate crisis by the two other major crises they will inherit: Covid-19 and an economy in bad need of a reboot. Biden will become president in a multiple crisis situation similar to the one that he and Barack Obama inherited when the world economy was on the verge of collapse. They succeeded at pulling the world back from the brink and went on to achieve the long-awaited goal of making affordable health care available to millions of more Americans. But climate change was pushed aside. By the time they got to it, their political capital was mostly spent.

Biden will have to pick a highly qualified team to help him multi-task on domestic and international climate action while beating the coronavirus and reviving the economy. Again, he can achieve that triple play by making clean energy investments a central part of economic stimulus.

Insofar as the United States is held up as a model of democracy, it is also an example of how difficult it is to solve permanent problems with temporary leaders. The only way to do it is with public support so strong that leaders would not dare defy it, and so deeply valued that it is passed from generation to generation.

Achieving those goals – an enduring public mandate and the infusion of climate-change mitigation and adaptation into every relevant government investment and program – will be Joe Biden’s next big challenge. Many of us in the United States want to make sure that he does not face the challenge alone.