Ukraine's president is visiting the White House. Biden can't afford to play nice anymore.

• Ukrainian President Volodymyr Zelenskyy will meet with President Joe Biden at the White House on Wednesday.
• US interests in Ukraine are principally about avoiding conflict with Russia, and Biden won't do himself or Zelenskyy any favors if he continues to back up Ukraine's maximalist positions.
• Matthew Mai is an intern at Defense Priorities.

In June, President Joe Biden hosted former Afghan President Ashraf Ghani at the White House. Notably, he did not bother masking the inevitable security challenges the government would face once US troops left the country, saying, "Afghans are going to have to decide their future, what they want."

The message was clear: After 20 years, $2 trillion in costs, and 2,500 Americans killed, the reality on the ground in Afghanistan was not going to be fundamentally changed by continued US military involvement.

When Ukrainian President Volodymyr Zelenskyy visits the White House on Wednesday, Biden has another opportunity to bring that same realism to bear.

When Russia deployed infantry and armor units to Ukraine's eastern border back in the spring, the administration offered its support for Ukraine's "sovereignty, territorial integrity, and Euro-Atlantic aspirations." More specifically, the US does not officially recognize Crimea or Donbas as part of Russia and supports Ukraine eventually becoming a member of NATO.

Despite these official positions, the Biden administration's policy decisions instead reflect the constraints on US power abroad and the peripheral importance of Ukraine's security to US national interests.

Rather than alienate Germany - a country Biden's foreign policy team views as a key ally - the administration waived sanctions on the controversial but nearly completed Russian Nord Stream 2 pipeline. Both Ukraine and the Baltic states understandably view this as a threat to their energy security and made their displeasure known.

And while the administration maintains that more anti-corruption reforms are needed from Kyiv before it can join NATO, Biden and his team know that France and Germany both oppose voting on Ukrainian membership since doing so would trigger another crisis with Russia overnight.

Fortunately, for all of the "democracy v. autocracy" talk, even this liberal internationalist administration recognizes the basic limits of its ideological worldview when it comes to dealing with other great powers.

Therefore, just as Biden leveled with Ghani before the inevitable fall of Kabul, he should be equally honest with Zelenskyy in outlining US interests.

Currently, the biggest problem between Kyiv and Moscow is the ongoing conflict in the eastern region of Donbas where two self-declared Russian-backed separatist republics, Donetsk and Luhansk, are battling Ukrainian government forces.

Frustratingly, the Minsk 2 agreement signed between Ukraine and Russia has never been implemented given the routine violations of the critical ceasefire measure.

But as far as US policy is concerned, the legitimacy of Ukraine's territorial claims face potent challenges on the ground in Donbas.

Since 2019, over a half-million Russian passports have been given to people in the region. In both Crimea and Donbas, over three-quarters of the inhabitants speak Russian. Unsurprisingly, pro-Russian political parties do well in the semi-autonomous regions of Donetsk and Luhansk.

The Ukrainian government has refused to negotiate with the two would-be republics since doing so would amount to a de facto acceptance of their sovereign claims. Instead, throughout the summer, Kyiv has waged an aggressive public relations campaign to join NATO and the EU.

In an interview with Reuters before the NATO summit, Zelenskyy demanded that Biden be more specific about the roadmap for membership in the alliance.

The Ukrainian minister of foreign affairs took to the pages of Foreign Affairs to assert that, "[i]n Ukraine and elsewhere, cutting ties with Moscow will proceed no matter what Putin or his entourage has to say about it."

This is a brazenly maximalist position for Kyiv to take even though its leaders correctly assume Russia has no intention of letting Donbas lose its self-declared autonomy.

By pushing for NATO membership, Kyiv wants the US to help solve Ukraine's territorial disputes militarily by invoking the Article Five mutual defense clause. Moscow knows this, which is why it has threatened that "those who would try to start a new war in Donbass - will destroy Ukraine."

Biden's message to Zelenskyy should instead make it clear that NATO membership is off the table and resolving the situation in Donbas is for Kyiv and the separatists to work out between themselves.

US interests in Ukraine are principally about avoiding conflict with Russia. The administration is not doing itself or Kyiv any favors if it continues to offer rhetorical assurances that the US will back up its position.

Matthew Mai is an intern at Defense Priorities. Previously, he was a fall 2020 Marcellus policy fellow with the John Quincy Adams Society.