The Ukrainian military has defeated Russia’s initial war campaign, setting up the possibility of a sustained “stalemate” throughout much of the country, according to the Institute for the Study of War.

Russian forces had sought to utilize “airborne and mechanized operations” to seize various population centers, including the Ukrainian capital, Kyiv, and the cities of Kharkiv and Odessa. After more than three weeks, the Russians “continue to make limited advances” but are “very unlikely to be able to seize their objectives,” according to the institute’s latest assessment of the war, released Saturday afternoon.