CDR: why should it be trusted?

I don't know much about crypto politics, but... isn't it utterly obvious that the mere fact that the NSA suggest a certain algorithm (say Rijndael) for a national standard and recomends its use internationally imply that they have a pretty darn good idea (if not actual technology) on how to break it efficiently? I just don't see why else they would advocate its use. After all isn't the fact that NSA could break DES since the 70's the reason for the 'success' of DES?