What if a government agency does something "unconstitutional", who determines it is unconstitutional? If the answer is "we the people", then where does that "people" (individual or group) take their "unconstitutional conclusion, to the Legislative representative, Executive representative, or Judicial representative, for review?
Judicial Review is NOT a power delegated to the Supreme Court. Ther job is to defend the Constitution not to interpret it. It is the job of "We the People" through our representatives to determine what is and what is not Constitutional.