The liberals are trying to popularize the notion that you are not qualified to sit on the Supreme Court unless you've served in the federal appellate system because they know that if they can limit the potential choices to the federal appellate judges, then they will inevitably be liberals.
But the truth is that you don't have to be a federal appellate judge to be on the Supreme Court, and in fact, the majority of the justices (if not all) currently on the Court did not come up thru the federal system.
That's true. It's not a requirement.
So is Rush Limbaugh.