The war in Ukraine shows no sign of abating, let alone ending. Unable to make headway on the battlefield, Russia has been bombarding Ukraine’s electrical infrastructure in hopes of freezing Ukrainians into submission as winter looms. The Ukrainians continue to press their offensive against Russian troops, many ill-trained and poorly motivated, to gain as much territory as possible before the cold sets in.

The United States continues to provide economic aid and armaments to Kyiv. Another $275m in weapons and ammunition was pledged on 27 October, taking total US financial, military and humanitarian aid to more than $50bn since January. Additional assistance is certain.

As the war drags on, the debate back home on how the US should handle it is likely to get more pointed and accusatory. Indeed, we may have already reached that point. Today, anyone broaching the subject of peace negotiations, let alone proposing ideas for a settlement, invites accusations of furthering Vladimir Putin’s narrative or providing aid and comfort to the enemy. The Congressional Progressive Caucus learned this the hard way recently, when its letter to President Biden proposing diplomacy to end the war was immediately vilified.

That’s more than lamentable; it’s harmful. It’s during times of war that serious, unfettered discussion about the stakes, costs and risks of a particular policy choice is not only appropriate but absolutely essential. Arbitrarily policing the debate not only does a disservice to free thought but potentially leads to a situation whereby common-sense policy options are dismissed. Reasoned debate becomes a casualty.

Facts on the ground make clear that the likelihood of immediate negotiations are virtually nil. Ukraine’s forces are making slow but steady progress and are trying to push Russian troops out of Kherson, so Kyiv has no reason to sue for peace. Moreover, Ukraine rightly fears that a ceasefire would leave about a fifth of its territory in Putin’s hands and give him a respite to regroup his army and then resume the offensive.

Alleged Russian war crimes in Bucha, Mariupol and elsewhere have made Ukraine all the more determined to win the war. Meanwhile, Putin’s unlawful annexation of Donetsk, Luhansk, Zaporizhzhia and Kherson last month have further convinced Ukrainian president Volodymyr Zelenskiy that talks aren’t possible.

Still, although talks may be infeasible now, they may be possible later on.

War is inherently unpredictable. The side advancing today could be retreating tomorrow – or six months later. The course of this war makes this evident. Early this summer, the Russian army, using its superiority in artillery, pummeled Ukrainian positions in Luhansk and captured the towns of Sievierodonetsk and Lysychansk; Ukrainian troops suffered heavy losses. Two months later, Russian troops were beating a chaotic retreat and the Ukrainian army regained more than 3,000km of land in Kharkiv province within days.

The tide could turn again once as tens of thousands of new Russian recruits (even if many are poorly armed, equipped and trained) join the fray and enable a Russian counteroffensive. The same Ukrainian government that now regards talks as pointless may then be open to them if it helps them avoid losing even more land. This may not happen, but the possibility that it could means that suggestions for a settlement should not be demonized.

As the war continues – for months, perhaps years – the economic costs to the west in arms and economic aid to Ukraine, already substantial, will increase, particularly if Russia continues its relentless attacks on Ukrainian economic assets. Moscow’s slashing of energy exports has already contributed to an economic crisis in Europe. Germany, the EU’s largest economy, risks slipping into a recession and has had to mobilize $200bn to help consumers and businesses battered by high energy prices. France and Spain saw their GDPs contract in the July-to-September quarter. Eurozone inflation reached 10.7% in October, a record high. In the Baltic countries, the rate exceeds 22% as fuel and food prices have rocketed.

If Europe’s economic conditions get even worse and a recession occurs in the US, it isn’t far-fetched to imagine calls for a settlement becoming more palpable if it helps reduce the economic burden.

Moreover, there is always the possibility that the war could escalate, potentially drawing Russia and Nato into a direct confrontation. Hence proposals to prevent this denouement through diplomacy should be welcomed.

Many dismiss the risk of escalation and Putin’s nuclear saber-rattling as empty rhetoric. Perhaps it is. But none of us can know what Putin would do if Russian conventional forces continued to lose ground or were facing a complete defeat. Policymakers don’t have the luxury of planning for the best-case scenario or hoping Putin will respond the way we expect him too. We should be humbler about our powers of prognostication: two years ago, who would have foreseen Europe witnessing its worst war in nearly eight decades?

None of this means a deal with Putin should be cut behind Ukraine’s back. Nor should the US necessarily lead the process; simple geography suggests that Europe should play a larger role on all fronts in addressing the gravest threat to its security in a generation.

The notion that offering proposals for ending the war betrays Kyiv and aids Moscow is absurd. We need constructive discussions about diplomatic solutions. One day, they will be needed.

• Rajan Menon is the director of the grand strategy program at Defense Priorities, a professor emeritus at the Colin Powell School for Civic and Global Leadership at the City College of New York, and a senior research fellow at the Saltzman Institute for War and Peace Studies at Columbia University. He is the co-author of Conflict in Ukraine: The Unwinding of the Post-Cold War Order

• Daniel R DePetris is a fellow at Defense Priorities and a foreign affairs columnist for the Chicago Tribune and Newsweek, among other publications