No, it's not legal- even if that animé is not licensed in the United States. The Berne Convention is a treaty that protects International Copyrights. Japon and the US are both member States, party to this treaty. So when toi download and mettre en ligne copies of something that is copyrighted in Japan, then toi are violating international law.
NOW, there is one thing to understand. Even though par the definition of the law, it is illegal, in practice it is hardly something that is ever enforced. Local companies that have licensed animé (eg Funimation) have taken action against US citizens (usually in the form of Cease and Desist orders), but I have yet to hear of a Japanese company taking action against a US citizen for downloading / uploading unlicensed anime. However, Japon has become plus and plus proactive about this sort of thing lately.
And also, Japon and license companies such as Funimation usually go after the source directly, and largely ignore us little people. Fansub groups and animé hosting sites are fair game, however.
So to sum up: Yes it is a violation of International Law (via the Berne Convention) to download and mettre en ligne anime- however, it is highly unlikely for toi to get in trouble for merely torrenting anime- usually they go for bigger fish. However, toi still torrent at your own risk.