Mr Kuehne faces charges of money laundering and wire fraud for vetting $5.2 million worth of legal fees given to criminal defense attorney Roy Black by a leader of Colombia's Medellin drugs cartel, Fabio Ochoa, Law.com said.
In his assessment, Mr Kuehne said the money was legitimate and was not the proceeds of crime.
US district judge Marcia Cooke told prosecutors in a Miami court that federal statutes appear to support the defense counsel's argument that Mr Kuehne is exempt from prosecution.
According to the Associated Press, defense lawyers cannot be prosecuted even if they know the fees they accept are from criminal activity.
However, senior assistant US attorney Robert Feital contested that lawyers who launder funds are complicit and the use of the exemption is an "affirmative defese" that should be put before a jury.
Mr Feital added that the charges against Mr Kuehne do not contradict the constitutional right to counsel of choice because he was not representing Mr Ochoa.