Damn straight!

Trop v. Dulles, 356 U.S. 86 (1958), was a federal court case in the United States that was filed in 1955, and finally decided by the Supreme Court in 1958. The Supreme Court decided, 5-4, that it was unconstitutional for the government to cancel the citizenship of a U.S. citizen as a punishment. The ruling's reference to "evolving standards of decency" is frequently cited precedent in the court's interpretation of the Eighth Amendment's prohibition on "cruel and unusual punishment."

In the dissent, Justice Felix Frankfurter noted that desertion from the military can be punished by the death penalty, leading him to ask, "Is constitutional dialectic so empty of reason that it can be seriously urged that loss of citizenship is a fate worse than death?"
-http://en.wikipedia.org/wiki/Trop_v._Dulles