Wars often erupt and persist because of the two sides’ miscalculations regarding their relative power.

In the case of Ukraine, Russia blundered badly by underestimating the resolve of Ukrainians to fight and the effectiveness of NATO-supplied weaponry. Yet Ukraine and NATO are also overestimating their capacity to defeat Russia on the battlefield. The result is a war of attrition that each side believes it will win, but that both sides will lose.

Ukraine should intensify the search for a negotiated peace of the type that was on the table in late March, but which it then abandoned following evidence of Russian atrocities in Bucha — and perhaps owing to changing perceptions of its military prospects.