It’s grim—and official: Donald Trump is returning to the White House. No doubt the time between now and January 20 will be a time of reckoning and recriminations about how the Democratic Party failed to fend off a profoundly flawed authoritarian—for the second time.

But all the while, the White House will remain occupied by Joe Biden. And now the first one-term Democratic chief executive since Jimmy Carter has a few weeks to make a last-ditch effort to salvage his legacy—and shore up the governmental guardrails that Trump imperils.

There is far more good that the Biden administration could do in its waning days than can possibly be named here. (The list of worthy pardons alone would be staggering.) But in particular, President Biden has clear opportunities when it comes to reforming criminal justice, brokering global peace, protecting immigrants, taking climate action, and fending off authoritarianism.

First, he can bring to fruition a reform he’s already begun to explore: legalizing marijuana. Back in May, Biden initiated a review of cannabis’s status as a Schedule I drug, a pivot away from his long-standing opposition. It’s debatable exactly how much authority the president has to change marijuana’s legal status. But Biden could certainly conclude his administration’s needlessly lengthy review process—how long does it take to say, “It’s not a gateway drug”?—and officially recommend de-scheduling to federal agencies. He could also pardon anyone currently languishing in federal prison for nonviolent drug offenses. Since these prospective pardon recipients are disproportionately Black, the move would advance not just criminal but also racial justice. And crucially, making such moves would deny Trump the easy victory of making any of them himself.

In another commonsense change that would undo decades of senseless policy, the president could also finally normalize relations with Cuba. That would mean the restoration of official diplomatic ties, removal of the island from the State Sponsors of Terrorism List, and honoring the 22 bilateral agreements signed during the Obama administration before being torn up by Trump. It would also mean lifting sanctions that have fueled Cuba’s ongoing economic crisis, and providing robust aid to people beset by severe fuel shortages and food rationing. Closing Guantánamo Bay Naval Base and returning it to Cuba as a hospital would disassemble the starkest symbol of American domineering on the island. And though Trump will almost certainly seek to reverse any executive actions on Cuba, Biden could make that politically complicated by opening up private-sector investment there.

That’s not the only unfinished diplomacy at stake. The backdoor conversations between Trump and Benjamin Netanyahu—and ”backdoor” here means “openly discussed”—were dispiritingly evocative of the alleged Republican efforts in 1980 to delay the release of American hostages in Iran until after Reagan defeated Carter and took office. Now, whether the horrors escalate or a ceasefire is brokered that Trump gets undeserved credit for, this conflict is set to go down as Biden’s signature foreign policy failure. But he still has time, in the twilight of his presidency, to assert some moral authority by enforcing the Leahy Law—which prevents the US from providing military aid to a country that has violated human rights—and halting, even temporarily, arms shipments to Israel.

As he makes his final efforts to curb humanitarian crises in Gaza and Cuba, Biden might also try to avert a future one along the United States’ southern border. Trump has threatened to double down on the cruel immigration policies of his first term through “the vast arsenal of federal powers.” That could include the mass deportation of 11 million undocumented immigrants, as well as a resumption of his family separation policy at the border. President Biden can try to stymie this sadism by fast-tracking citizenship applications, reversing an executive order restricting asylum, and expanding work permits for undocumented immigrants. These compassionate reforms could profoundly change the outlook for many people who might otherwise be under threat in January and beyond.

Meanwhile, with at least 3 million Americans already forced by extreme weather to become climate refugees, Biden has more than enough reason to declare a climate emergency. He claims to have “practically” done so, but actually doing so would enable him to circumvent a stubborn Congress to allot additional climate funding. Then, he can implement a raft of overdue executive orders, from more niche but nonetheless consequential reforms like decarbonizing the maritime industry, to sweeping (and promised) changes like banning offshore drilling. Such action would cement Biden’s legacy as arguably the greenest president in modern history—and force Trump to make unfavorable headlines if he wants to undo that progress.

Finally, Biden must take concrete steps to fend off the threat of authoritarianism that Trump’s second term poses. American democracy may now be in its most vulnerable position since the Civil War. That’s why filling all 46 judicial vacancies with judges who will uphold the rule of law is nonnegotiable. He can also reach across the aisle to address concerns about election integrity—before Trump takes that matter into his own paws—by replacing antiquated voting machines, conducting audits, and protecting poll workers and election officials.

Above all, a productive, placid lame-duck period would do much to demonstrate for the first time in eight years what a peaceful transfer of power looks like—even as Biden hands it back to the person responsible for that lapse.

Weeks after he had conducted a different kind of transfer of power, on the first night of this year’s Democratic National Convention, Biden summed up his hopes for his legacy: “Let me know in my heart…that I gave my best to you.” Between now and January, he can do his best to align that self-evaluation with history’s judgment.