On 24 October, 30 members of the House Democratic Progressive Caucus released a letter to Joe Biden calling for a “proactive diplomatic push” on Kyiv to work toward a ceasefire and “direct [US] engagement” with Moscow to end the Russia-Ukraine war. One week earlier, Republican House leader Kevin McCarthy’s no “blank check” for Ukraine comment raised questions about future congressional support for US assistance to that embattled country.

The letter, even though it has now been withdrawn, and McCarthy’s comment are unfortunate. Vladimir Putin will take encouragement from both as Russia wages its war. The suggestion of cracks in US backing for Ukraine will increase his incentives to continue fighting.

The war has not gone as Putin hoped. The Russian army failed to take Kyiv. More recently, the Ukrainian military, fighting with skill, courage and tenacity, has driven Russian forces back in the east and south of the country and appears poised to recover further territory.

Crucial to Ukraine’s success, however, is the flow of US arms. The Kremlin would like nothing more than a future Congress cutting funds for the weapons on which Ukraine depends.

Moscow also would welcome US pressure on Kyiv to seek a ceasefire or American readiness to negotiate directly with Russia on a ceasefire or broader settlement. While one can understand the desire for an end to the war, the sides at present have nothing to negotiate. The original Russian demands of Ukraine – including neutrality, demilitarization and recognition of Crimea as Russian and of the so-called Donetsk and Luhansk “people’s republics” as independent states – amount to the Ukrainians’ total capitulation.

Moreover, despite battlefield reverses, Russia’s demands have increased. Moscow now wants Kyiv to recognize its annexation of Donetsk, Luhansk, Zaporizhzhia and Kherson, even though Russian forces do not control all of those regions. Why should Kyiv engage in a negotiation that Russian demands mean would focus on how much Ukrainian territory to concede?

Revelations of torture chambers, summary executions, filtration camps and other war crimes in places such as Bucha, Mariupol and Izium have hardened the Ukrainians’ resolve to resist. From Kyiv’s perspective, Russia’s terms offer little more than surrender and subjecting more of its citizens to similar atrocities. Unsurprisingly, the Ukrainians will not agree.

Even a ceasefire now poses danger for Ukraine. Nothing suggests the Russians would withdraw as part of a ceasefire arrangement, so it would mean leaving Russian units occupying Ukrainian territory. Ukrainians have seen this before: the February 2015 Minsk II ceasefire left Russian and Russian proxy forces in control of parts of Donetsk and Luhansk. They never yielded that territory back. Moreover, Russia could exploit a ceasefire in place to regroup and rebuild its forces in order to launch new assaults at a time of its choosing.

For Ukraine, seeking negotiations in the current circumstances has zero appeal. As for “direct engagement” with Moscow, US officials should not negotiate with Russian officials over the heads of Ukrainians. Washington has no right to do that.

To be sure, a time may come for negotiations between Kyiv and Moscow. That will require significant changes in the Kremlin’s negotiating position, probably only after further battlefield losses. And any decision to negotiate while Russian forces remain on Ukrainian territory should be left solely to Kyiv.

Strong continued US financial and materiel support for Ukraine’s effort to drive the Russian military out thus is central to ending the war on acceptable terms.

Neither the authors of the now-withdrawn letter nor McCarthy seem to fully understand these points or the key US interests at stake. The United States has long had a vital national interest in a stable and secure Europe. A Russian victory, or an unsustainable peace that would collapse when Moscow chose to renew its war, would mean much greater instability in Europe.

Further, US officials must consider what Putin might do if bolstered by a win in Ukraine. He has talked of recovering “historic” Russian land, which is how he regards most of Ukraine. The Russian Empire once included the Baltic states. Might an emboldened Putin be tempted there?

Supporting Ukraine means the US providing money and arms and trusting the Ukrainians’ judgment on negotiations. Supporting the Baltic states, Nato members, would mean money, arms and the lives of American soldiers. It is better to stop Russia in Ukraine. Premature negotiations or cutting funding to Kyiv will not achieve that.