Translate the following English sentence to French:
"The major problem is not that no measures are being taken against crimes committed against the Union but, rather, that these are committed so often and far too seldom discovered."
Le problème majeur n' est pas l' absence de poursuites à l' encontre des auteurs d' actes criminels commis aux dépens de l' Union, mais le fait que ces actes soient si fréquents et qu' on les découvre si rarement.