[divemedic]

You said that a writ of certiorari is not an appeal. It most certainly is. The way the SCOTUS works is that a party appeals a decision of the Circuit Court of Appeals to the SCOTUS. This appeal is called a Petition for Writ of Certiorari.

The court reviews the appeal, and the SCOTUS Justices take a vote on whether or not to hear the case. A minimum of four Justices must vote to hear the case. If the case gets the required 4 vote minimum, the court issues a Writ of Certiorari, this is known as "granting cert."

A Writ of Certiorari is an instruction from the SCOTUS, directed at the appeals court, instructing the lower court to deliver the record of the case to the SCOTUS for review. The court cannot hear a case that has not been appealed from a lower court. They cannot just decide to insert an opinion whenever they feel like it. In fact, there are only 6 circumstances that can cause cert to even be considered:

* By petition for a writ of certiorari, filed by a party to a case that has been decided by one of the United States courts of appeals or by the United States Court of Appeals for the Armed Forces.
* By petition for "certiorari before judgment," which permits the Court to expedite a case pending before a lower appellate court by accepting the case for review before the appellate court has decided it. However, Supreme Court Rule 11 provides that a case may be taken by the Court before judgment in a lower court "only upon a showing that the case is of such imperative public importance as to justify deviation from normal appellate practice and to require immediate determination in this Court."
* By appeal from certain decisions of United States district courts in certain cases involving redistricting of congressional or state legislative districts, or when specifically authorized in a particular statute.
* By petition for writ of certiorari with respect to a decision of one of the state courts (including courts of Puerto Rico and the District of Columbia), after all state appeals have been exhausted, where an issue of federal constitutional or statutory law is in question. The writ is usually issued to a state supreme court, but is occasionally issued to a state's intermediate appellate court for cases where the state supreme court denied certiorari or review and thereby refused to hear the appeal.
* By a certified question or proposition of law from one of the United States Courts of Appeals, meaning that the Court of Appeals requests the Supreme Court to instruct it on how to decide the case. This procedure was once common but is now rarely invoked; the last certificate accepted for review was in 1981.
* By petition for an "extraordinary writ" such as mandamus, prohibition, or habeas corpus. These writs are rarely granted by the Supreme Court though they are more frequently granted by lower courts.

The only thing that is discretionary about this process is that the court may deny cert because the requisite 4 Justices did not vote to grant it.