North Korean troops have begun fighting in Russia's Kursk region, as part of a major Russian offensive.

Russian drone and missile strikes on Ukrainian targets have increased in frequency in the week since the U.S. election, killing civilians and destroying another dam. Russian troops continued to make incremental gains toward the city of Pokrovsk. The Russian army is preparing a new offensive, this time using North Korean troops. Russian President Vladimir Putin congratulated Donald Trump on his election but implied that he would have discussions only if the U.S. initiates talks, drops its sanctions, and refuses to offer any further support for Ukraine—accepting, in other words, a Russian victory. Meanwhile, Russian state television welcomed news of the election by gleefully showing nude photographs of Melania Trump on the country’s most-watched channel.

How will the new U.S. administration respond? What should the outgoing administration do?

In one sense, nothing will change. For nearly three years, many, many people, from the right to the left, in Europe and in America, have called for negotiations to end the Russian invasion of Ukraine. The Biden administration repeatedly probed the possibility of negotiations. The German government endlessly proposed negotiations. Now a new team will arrive in Washington, and it will be demanding negotiations too.

[Read: Helping Ukraine is Europe’s job now]

The new team will immediately run into the same dilemma that everyone else has encountered: “Land for peace” sounds nice, but the president of Russia isn’t fighting for land. Putin is fighting not to conquer Pokrovsk but to destroy Ukraine as a nation. He wants to show his own people that Ukraine’s democratic aspirations are hopeless. He wants to prove that a whole host of international laws and norms, including the United Nations Charter and the Geneva conventions, no longer matter. His goal is not to have peace but to build concentration camps, torture civilians, kidnap 20,000 Ukrainian children, and get away with it—which, so far, he has.

Putin also wants to show that America, NATO, and the West are weak and indecisive, regardless of who is president, and that his brutal regime represents some kind of new global standard. And now, of course, he also needs to show his country that nearly three years of fighting had some purpose, given that this costly, bloody, extended war, officially described as nothing more than a “special military operation,” was supposed to end in a matter of days. Maybe Putin could be interested in stopping the fight for some period of time. Maybe he could be threatened into halting his advance, or bribed with an offer of sanctions relief. But any cease-fire treaty that does not put some obstacle—security guarantees, NATO troops in Ukraine, major rearmament—in the way of another invasion will fail sooner or later because it will simply give Russia an opportunity to rest, rearm, and resume pursuit of the same goals later on.

Putin will truly stop fighting only if he loses the war, loses power, or loses control of his economy. And there is plenty of evidence that he fears all three, despite his troops’ slow movement forward. He would not have imported thousands of North Korean soldiers if he had an infinite number of Russians to replace the more than 600,000 soldiers whom he has lost to injury or death. He would not have paid American YouTubers to promote anti-Ukrainian propaganda if he wasn’t worried by the American public’s continued support for Ukraine. His economy is in trouble: Russian inflation is rising fast; Russian interest rates are now at 21 percent; Russian industries particularly vulnerable to sanctions, such as liquefied natural gas, are suffering. The Russian navy was humiliated in the Black Sea. The Russian military has still not recaptured territory lost in Russia’s Kursk province, conquered by the Ukrainians last summer.

When the next U.S. president, secretary of defense, and secretary of state take office, they will discover that they face the same choices that the current administration did. They can increase Putin’s agony using economic, political, and military tools and make sure he stops fighting. Or they can let him win, quickly or slowly. But a Russian victory will not make Europe safer or the U.S. stronger. Instead, the costs will grow higher: A massive refugee crisis, an arms race, and possibly a new round of nuclear proliferation could follow as European and Asian democracies assess the new level of danger from the autocratic world. An invasion of Taiwan becomes more likely. An invasion of a NATO state becomes thinkable.

[Karl Marlantes and Elliot Ackerman: The abandonment of Ukraine]

In the final two months of his presidency, Joe Biden, together with Ukraine’s European allies, will have one last chance to push Russia hard, to respond to the extraordinary Russian–North Korean escalation, and to stabilize the Ukrainian front line. This is Biden’s last chance to allow Ukraine to carry out long-range strikes against targets inside Russia. Although the Russians can strike any target, military or civilian, anywhere in Ukraine and at any time, the Ukrainians have been limited to their own drones. They have had some startling successes—their drone operations are now the world’s most sophisticated—including hitting military factories all over Russia, and several targets in Moscow this week. But to stop attacks on their cities and to prevent the Russian military from moving troops and equipment toward their borders, they need to be able to use missiles to hit air bases and logistical hubs inside Russia too.

Even more important is the question of money. Biden must press upon the Europeans, as a matter of urgency, the need to transfer frozen Russian assets to Kyiv—not just the interest but the capital. This money—more than $300 billion—can be used to purchase weapons, rebuild the country, and keep the economy going for many months. Most of this money is in European institutions whose leaders have delayed making final decisions about it for fear that Russia will retaliate against European companies, especially French and German companies that still have assets in Russia. But now time is running short: Perhaps the Trump administration will preserve sanctions on Russia, but perhaps it will not.

Biden’s team says it will expedite the delivery of the remaining weapons and resources that Congress has already designated for Ukraine. The goals should be to stabilize the front lines and prevent a collapse in Ukrainian morale; to provide long-term support, including spare parts so that repairs and maintenance of existing weapons systems can continue; and, most of all, to hit the North Korean troops in Kursk. It’s very important that the North Korean leadership perceives this escapade as a catastrophic failure, and as quickly as possible, so that more troops aren’t sent in the future.

After that? The choices, and the stakes, remain very similar to what they were in February 2022. Either we inflict enough economic pressure and military pain to convince Russia that the war can never be won, or we deal with the far more ominous, and far more expensive, consequences of Ukraine’s loss. Biden has a few more weeks to make a difference. It will then be up to Trump to decide whether he will help Ukraine to succeed and to survive, or whether he will push Ukraine to fail, along with the broader democratic world.

Ukraine's president says the incursion is limiting the forces Moscow can deploy inside his country.

Ukraine launched a surprise incursion into the Russian border region in August.

Ukraine says it has started fighting North Korean troops in Kursk, but could eliminate them in their front-line bases.

Ukraine and its allies say some North Korean soldiers are already deployed to fight in the Russian region of Kursk.

Ukrainian President Volodymyr Zelenskyy says 11,000 North Korean troops are in Russia’s Kursk region bordering Ukraine.