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Page Number: 16

12 

XIULU RUAN v. UNITED STATES 

Opinion of the Court 

the outset of every Controlled Substances Act prosecution,
every exception in the statutory scheme.

Section  885  thus  does  not  provide  a  basis  for  inferring 
that Congress intended to do away with, or weaken, ordi-
nary and longstanding scienter requirements.  At the same 
time,  the  language  of  §841  (which  explicitly  includes  a
“knowingly or intentionally” provision); the crucial role au-
thorization (or lack thereof ) plays in distinguishing morally 
blameworthy conduct from socially necessary conduct; the 
serious nature of the crime and its penalties; and the vague, 
highly  general  language  of  the  regulation  defining  the 
bounds  of  prescribing  authority  all  support  applying  nor-
mal scienter principles to the “except as authorized” clause. 
That  statutory  requirement,  while  differing  from  an  ele-
ment in some respects, is sufficiently like an element in re-
spect to the matter at issue here as to warrant similar legal 
treatment. 

And the Government does not deny that, once a defend-
ant claims that he or she falls within the authorization ex-
ception and the burden shifts back to the Government, the
Government must prove a lack of authorization by satisfy-
ing  the  ordinary  criminal  law  burden  of  proof—beyond  a 
reasonable  doubt.    See  Brief  for  United  States  26;  Tr.  of 
Oral Arg. 50–51; see also id., at 62–65.  But see post, at 10– 
11  (concurrence  suggesting,  contrary  to  the  position  ad-
vanced by all parties to these cases, that the Government 
need only prove lack of authorization by a preponderance of
the evidence).  Once the defendant meets his or her burden 
of production, then, the Government must prove lack of au-
thorization beyond a reasonable doubt.

Resisting the “knowingly or intentionally” standard, the
Government instead offers a substitute mens rea standard. 
The  Government  says  that  rather  than  simply  apply  the 
statute’s  “knowingly  or  intentionally”  language  to  the  au-
thorization clause, we should read the statute as implicitly 
containing  an  “objectively  reasonable  good-faith  effort”  or