Six weeks into its military incursion in Russia, Ukraine has shown why it is not really seeking territorial conquest. On Monday, it invited the International Committee of the Red Cross to inspect whether Ukrainian soldiers have followed the rules of war as an occupying force over foreign civilians.

“Ukraine is ready to ... prove its adherence to international humanitarian law,” Ukrainian Foreign Minister Andriy Sybiga wrote on social media.

In other words, having taken the military high ground in Russia’s Kursk region, Ukraine now seeks the moral high ground in the court of world opinion.

Since the war began in early 2022, Ukrainian President Volodymyr Zelenskyy has said Ukraine must fight by the rules of the Geneva Conventions, which have been adopted by nearly every country and are administered by the International Committee of the Red Cross. By safeguarding Russian civilians and prisoners of war in Kursk, Ukraine can convince more countries not to support Russia in any way.

Ukraine’s qualitative difference from Russia’s reckless treatment of Ukrainians has become a force unto itself. Ukraine relies on a principle of law calling for the protection of innocent noncombatants as well as wounded or captured troops on the battlefield. “It is important for us not to be like those who brought war with looting and rape to us,” Mr. Zelenskyy said in late August.

Abiding by the rules of war has another effect for Ukraine. It boosts the morale of its soldiers.

“When soldiers are well-led, and engage in ethical conduct in war (as brutal as that might be at times), it keeps them human in the most terrible of circumstances, and also protects their souls,” Mick Ryan, a retired Australian general and military analyst, wrote on the social platform X about Ukraine’s compliance with the rules of war.

Last month marked the 75th anniversary of the Geneva Conventions. While often ignored in many of today’s nontraditional conflicts – such as in Gaza – the rules of war are still highly discussed among nations, indicating a preference to use law to limit wars to combatants and to spare the innocent.

“International norms are guidelines that tell states which actions are and are not appropriate and provide metrics against which to judge others’ conduct,” Tanisha M. Fazal, a political science professor at the University of Minnesota, wrote in Foreign Affairs.

“The norm against territorial conquest didn’t stop Russia from invading Ukraine,” she added, “but it does help explain why Moscow is paying such a high price for its land grab.”

Principles do have power, Dr. Fazal wrote, and beneath the surface of war, “Norms in fact work as a powerful motivator and constraint.”