Bormoir was good, he just didn't have the as strong the mental discipline as Araagorn or others. Aragorn lived in wilderness most of his life, so his mind was rugged and he was not bent on power. Frodo lived in the happy go lucky shire, and he never thought about power and war, he was completely oblivious actually. Boromir was raised up in a world were power and control was a virtue and a nescesity for survival. As a captain of the defense of Gondor his mind was always bent on defending Gondor and finding ways to make his country more powerful. Gondor would have fallen much earlier if Gondor was as releaxed as the Shire. So Bormir was mostly doing his job. Given Time Aragorn would have succumbed to the ring as Frodo, Gollum, Isuildor, and Bormoir did. Gandalph didn't want to even tough the ring, becuasse he was already so powerful and deep in the arts of magic he feared that he would get attached to the ring. So you cannot really blame Bormir for trying to take the ring. He was thinking logicly. The plan was for 9 warriors (which had been reduced to eight) to SNEAK INTO MORDOR, the largest, most powerful realm in ME, and try to destroy a weapon so vastly powerful that it could turn the balance of viuctory to either side. Bormir thought that this was fooly, and even though he knew Frodo was T3H CH0S3N 1!!!111, Bormir thought that it would be safer to keep this WMD safely behind thousands of troops and barricades. Logical thinking. Even when he tried to take the ring Gondor's defense was still his main priority.