Expect Joe Biden to pursue the most aggressive climate-change plan in U.S. presidential history should he win the election.

Driving the news: A sea change would come to Washington, D.C., but the aspirations he laid out in his campaign are far higher than what political reality allows.

Where it stands: Let’s take a look at the highlights when it comes to a potential Biden administration. Last week, I assessed a potential second Trump administration.

Congressional action

The centerpieces of Biden’s climate plan, including the $2 trillion in spending over four years and a goal of making the electricity grid carbon-free in 15 years, will probably need congressional legislation.

Where it stands: If Democrats win the Senate, they may try to push through a range of policies by using legislative rules that require closer to 50, instead of 60, votes out of 100, as is typically needed for legislation.

• This includes “budget reconciliation” for spending and tax measures (it’s how Democrats approved the Affordable Care Act), and, more significantly, removing the filibuster rule.
• It's not clear that Democrats would succeed in getting rid of the filibuster, and Biden hasn't committed to supporting the change, though he has suggested he's open to it.

Yes, but: Even if Democrats control both chambers of Congress and even if they use the legislative rules, major climate policy changes are far from guaranteed.

• Congress is likely to prioritize several pressing issues ahead of standalone climate policy, including economic stimulus. Funding for clean energy is likely to feature prominently there, though.
• It’s not just the number of Democratic senators that matter, but also the political leanings of those senators, and many of them are more moderate than climate activists on social media.
• Opponents of big climate policy are eyeing Democrats’ big ambitions.

“The more ambitious they are, the better chance we have of defeating them,” said Myron Ebell, who directs energy and environment at the conservative Competitive Enterprise Institute.

What I’m watching: Smaller policy changes can still occur that can have a big impact, including removing long-standing subsidies oil and gas companies receive and creating new and expanded clean-energy subsidies.

Personnel

Expect an intra-party battle over the types of people Biden would tap to lead key agencies and White House roles.

• At the center of the fight is a sentiment among progressives that many experts who worked in the Obama administration are ill-suited to lead an aggressive climate push because they've taken positions affiliated with fossil-fuel companies.
• Obama-era officials who may be in the administration again under Biden despite criticism from progressives include Ernest Moniz, Obama’s energy secretary, and Amos Hochstein, a top official in Obama's State Department.
• Others who have been mentioned who would represent more progressive views include Washington Gov. Jay Inslee (although he has suggested he's not interested in a Biden Cabinet post) and Ali Zaidi, a top climate adviser to New York Gov. Andrew Cuomo who is advising the Biden campaign.

Regulations

Expect a years-long slog to reverse Trump’s deregulatory agenda.

• This is Washington’s swinging pendulum: Biden would be at least the third president to mostly, if not completely, repeal his predecessor’s regulatory actions. This has become par for the course given congressional gridlock.

What I’m watching: How Biden's Environmental Protection Agency, along with a host of other federal agencies, could try to implement his goal of a carbon-free power system by 2035 if the congressional route fails.

• Crafting such a rule in a way that survives legal scrutiny from a more conservative Supreme Court where it would inevitably land would be a tough task.

Oil and natural gas

Oil and natural gas will take a hit with Biden’s likely move to ban new leasing of the fuels’ production on federal lands, though most production occurs on state or private lands.

• In the short term, counterintuitively, Biden could help the biggest oil and gas companies by boosting prices and pushing regulations that impose disproportionate burdens on smaller producers.

Renewable and other new energy technologies

Clean energy of all kinds, including renewables and electric cars, would see a huge boon under Biden. He would not only push favorable U.S. policy, but also increase the chances the world moves faster, thereby increasing the market globally.

Climate diplomacy

America will, once again, face reengaging on the global stage after retreating on climate change.

• After George W. Bush stepped back from an earlier climate treaty in the early 2000s, Trump did the same thing with the Paris Climate Agreement.

The intrigue: China’s recent missive against Trump’s lack of leadership on climate change is likely to resonate even if Biden wins, suggesting it won’t easily accept a change of political leadership in America as sufficient.

Go deeper:

• Why Biden went big on climate change
• How Trump's energy endgame could go