In an opinion article published in Foreign Affairs magazine this week, Burns wrote that Putin's war had severely impacted Russia in a variety of ways, such as isolating it globally and damaging its military and economy.
"At least 315,000 Russian soldiers have been killed or wounded, two-thirds of Russia's prewar tank inventory has been destroyed, and Putin's vaunted decades-long military modernization program has been hollowed out," Burns said, as cited by the businessinsider.com website.
"All this is a direct result of Ukrainian soldiers' valor and skill, backed up by Western support," he added.
Burns argued that there were many benefits for the United States to continue supporting Ukraine, a "relatively modest investment with significant geopolitical returns," businessinsider.com reported.
"For the United States to walk away from the conflict at this crucial moment and cut off support to Ukraine would be an own goal of historic proportions," he warned in his piece.
It would allow Russia to achieve its goal of conquering Ukraine or forcing it into an unfavorable peace deal, leaving Putin emboldened and more aggressive, Burns said.
His warning comes as the latest package of US aid to Ukraine has been on hold since October, when Republicans blocked it in Congress, businessinsider.com noted.
Russia invaded Ukraine on February 24, 2022, starting the largest armed conflict in Europe since World War II.
Thursday is day 708 of Russia’s war on Ukraine.