What is the test for determining whether a federal sentence is cruel and unusual?

As with claims under the California Constitution, in determining whether a sentence violates the federal constitutional guarantee against cruel and unusual punishment, a court may consider "the gravity of the offense and the harshness of the penalty." (Solem v. Helm (1983) 463 U.S. 277, 292.)¹¹ "Outside the context of capital punishment, successful challenges to the proportionality of particular sentences [under

Page 34

the federal Constitution are] . . . exceedingly rare." (Rummel v. Estelle (1980) 445 U.S. 263, 272.)