Document ID: ./input/supremecourt_opinions/opinions/21pdf/21-511_o75p.pdf
Page Number: 17

Cite as:  596 U. S. ____ (2022) 

3 

BREYER, J., dissenting 

we have instead kept it narrow and selective in its member-
ship”); Mohawk Industries, Inc. v. Carpenter, 558 U. S. 100, 
113  (2009)  (“[R]ulemaking,  ‘not  expansion  by  court  deci-
sion,’ [is] the preferred means for determining whether and
when prejudgment orders should be immediately appeala-
ble”).

We must therefore exercise caution before extending the
collateral  order  doctrine.    We  have  “stringent[ly]”  limited 
that doctrine to only those district court orders “[1] that are 
conclusive, [2] that resolve important questions completely 
separate  from  the  merits,  and  [3] that  would  render  such 
important  questions  effectively  unreviewable  on  appeal
from  final  judgment  in  the  underlying  action.”    Digital 
Equipment Corp., 511 U. S., at 867–868. 

II 
A 
The Court today extends the collateral order doctrine to
a new category of orders, which it describes as “[t]ranspor-
tation orders issued under the All Writs Act.”  Ante, at 5, 
n. 1.  The Court believes these kinds of orders are collateral 
and therefore immediately appealable because, it says, they 
“(1) conclusively require transportation; (2) resolve an im-
portant question of state sovereignty conceptually distinct 
from the merits of the prisoner’s claims; and (3) are entirely
unreviewable by the time the case has gone to final judg-
ment.”  Ibid. (citation omitted).  I agree that orders like the
one at issue here “conclusively require transportation” and
are largely “unreviewable by the time the case has gone to
final judgment.”  Ibid.  But I do not agree that such orders
“resolve an important question of state sovereignty concep-
tually  distinct  from  the  merits  of  the  prisoner’s  claims.” 
Ibid.  That is so for three reasons. 

First, transportation orders do not appear to me to be es-
pecially “important.”  Even if those orders are unreviewable