It depends on both the "due process" clause in the 14th Amendment (IMHO, a shaky one, but then again, I'm not a lawyer) and the interpretation of this little gem from Article IV:
Section 4. The United States shall guarantee to every state in this union a republican form of government, and shall protect each of them against invasion; and on application of the legislature, or of the executive (when the legislature cannot be convened) against domestic violence.It can be argued that, by amending Nevada's constitution in a manner wholly inconsistent with the procedures outlined in same, the SCON has introduced a non-republican (small "r") form of government to Nevada.