Alito's vote not necessarily "liberal"

The press is noting that Alito sided with the liberal justices in staying the execution in Missouri.  However, this vote does not necessarily mean he has sided with the Liberals.  Rather, he may very well only be staying the execution to preserve the status quo, so that the Court can rule on the constitutionality of lethal injection under the 8th Amendment's prohibition on cruel and unusual punishment.  This is an issue that is constinantly raised by death row prisoners, and needs to be answered by the Supreme Court.  He may very well intend to write an opinion enthusiastically supporting this means of execution, ending an avenue of appeal for hundreds of death row inmates.  There is nothing inherently liberal about his decision to vote for a stay.  The real question is how he votes on the merits.