On Thursday, President Joe Biden held a phone call with Ukrainian President Volodymyr Zelenskyy. That phone call wasn’t “perfect”—both in the sense that not everything went smoothly, and in the sense that Biden didn’t use the call as an opportunity to blackmail the Ukrainian leader into falsifying a story about a political opponent—but it did serve to deliver a critical message at a critical moment.

With Russian forces still gathered along Ukraine’s border, and the threat of further invasion very real, the message that Biden passed along was just this: The United States isn’t working with European allies about Ukraine, it’s making those decisions with Ukraine. Or, as Biden put it, they are emphasizing the principle of “nothing about Ukraine without Ukraine.” The Ukrainian government is party to all critical discussions and a key part of all the decisions being made. Biden also made it clear that the United States, and NATO, would “respond decisively if Russia further invades Ukraine.”

In addition to the call, the Biden administration is engaged in a whirlwind diplomatic effort, one that intended to alleviate fears of European nations that have become dependent on Russian natural gas, and to close the cracks being exploited by Vladimir Putin. 

In order to prevent an invasion, President Biden faces a challenge that goes beyond the massed Russian troops. He has to convince the allies to close ranks behind a single position, and he has to overcome right-wing forces in the U.S. intent on paying back Putin for the great amount of help he has provided to the Republican Party.

Biden appears to have set a baseline by saying that the United States is committed to “Ukraine’s sovereignty and territorial integrity” along with the promise for “decisive action.” Exactly what kind of action that may be, when Russia has close to 100,000 well-equipped forces on the scene, many of them with fresh experience gained in crushing opposition to Bashar Assad in Syria, isn’t exactly clear. The U.S., along with European nations, has been redeploying forces to put them closer to the site of the potential invasion, and the U.S. has increased the volume of military assistance going into Ukraine, but no country has yet set troops into the country to face off with Russian forces.

Still, as The New York Times reports, Biden is conducting a concerted effort to bring allied nations into the picture, and to make it clear that the threat to Ukraine is a threat to the stability of Europe as a whole. He has expanded the traditional ranks of the NATO “war council” beyond France, Germany, and the U.K. to include leaders of Italy, Poland, and the E.U.

It’s a deliberate effort to avoid the kind of confusion and disagreement that has occurred in the past, such as when Donald Trump agreed to withdraw from Afghanistan in a deal with the Taliban that was made without consulting other NATO members with forces on the ground—or when Biden himself accelerated the pace of the U.S. withdrawal.

The effort around Ukraine is described as a “much-needed diplomatic reset,” one that has so far involved over 180 high-level diplomatic meetings in the effort to get everyone on the same page. Those efforts have seen Biden emerge firmly in the role of leader in efforts to hold back Russia’s territorial aggressions—a return to a familiar role that seemed impossible under Trump.

Meanwhile, extensive pro-Russian propaganda on Fox News and other right-wing sites has made Republican leaders and candidates afraid to speak out against Russia, or figures like Tucker Carlson actively supporting Russia’s position. The vocal support for Russia among some Republicans, and silence from others, represents a notable weakness in national unity that has not gone unnoticed by either Putin or other European leaders.

Before sending a letter to Russian leaders on Wednesday, U.S. diplomats worked through drafts with European leaders and Ukrainian officials. The letter isn’t intended to solely represent the position of the United States, or even of NATO, but to summarize the standing of allies opposed to Putin conducting a further invasion of a nation Russia has already been ripping apart for decades.

The clearest result of that letter: A firm rejection of the idea that NATO membership should be closed to Ukraine or any other nation that wants to join the alliance. That rejection takes the top item on Putin’s wish list off the table.

As France 24 reports, there is another way in which Putin might back down while still proclaiming victory. Ongoing negotiations over the Minsk and Minsk II protocols—agreed to by Ukraine after the nation suffered a major Russian-backed military defeat in 2015—are ongoing in Paris. Representatives of Russia, Ukraine, France, and Germany are present in an effort to better define how Russia and Ukraine enforce an agreement that was supposed to end the constant low-level war that Russia has supported in eastern Ukraine. 

The first eight points of the agreement are concerned with enforcing that ceasefire. However, Russia has never ceased sending forces and military equipment into Ukraine and done nothing to slow the violence in the Donbas region. 

The ninth point in the protocols deals with Ukraine providing election for some form of political autonomy to Donetsk and Luhansk Oblasts, allowing them to create their own laws and set the terms of their cooperation with the government in Kyiv. Both Ukraine and Russia see this is as a first step toward cleaving the nation down the middle.

Ukraine was under huge pressure when the protocols were signed, with a large portion of its army about to be lost. Since then Ukrainian leaders have been insisting that the other parts of the protocol—the ones that deal with ceasefire—have to be implemented before they’ll talk about the sections on political autonomy for potentially breakaway regions. Russia has continually tried to move that ninth point to the front of negotiations.

If Russian diplomats can convince Ukrainian leaders to solidify what that political autonomy would look like, and set a timetable for elections and what comes after, along lines that suit Moscow, Putin might walk away from the current showdown claiming victory without actually conducting an expansive invasion. But Ukrainian leaders have, to date, considered every Russian proposal to be tantamount to handing over the Donbas.

President Biden mentioned the Minsk agreements in his talk with President Zelenskyy and expressed hopes for progress in their implementation. In the meantime, he acknowledged that the threat of an invasion is real.

Russia has positioned forces north and south of Ukraine, as well as east, making it difficult for the smaller Ukrainian army to take any defensive posture that might slow a Russian advance. It’s also making clear to European nations—particularly Germany—that interference in Ukraine could result in an abrupt shut down of Russian natural gas pipelines in mid-winter.