Western allies will have to grapple with a “very big Russia problem” regardless of how the war in Ukraine ends, according to NATO’s top general in Europe, who underscored eastern European fears that Russia threatens “the survival of their states.”

“The outcome on the ground in Ukraine is terribly, terribly important — vital to future European and global security,” U.S. Army Gen. Christopher Cavoli, the NATO supreme allied commander Europe, told the Aspen Security Forum on Thursday. “So supporting Ukraine is vital for our security. But we can’t be under any illusions: at the end of a conflict in Ukraine, however, it concludes, we are going to have a very big Russia problem.”