It's true that the state of California had it's one bite at the apple and, through the LA County DA's office, failed miserably. Double jeopardy would be to try the same person more than once on the same crime. I have always felt that there should have been a federal prosecution of O.J. and A.C.Cowlings for what may have been a before-the-fact conspiracy to commit the crime, or an after-the-fact-conspiracy to obstruct justice and cover it up. The cell phone and air phone calls that O.J. made (see the testimony of the driver who took him to the airport, see the testimony of those who recognized O.J. and observed him on the United red-eye to Chicago, using an "air-phone" to make several calls.) were almost undoubtedly to Cowlings, asking him to deep six some bags of bloody clothing left at O.J. residence. Unfortunately the LA County DA's office made such a mess of the investigation and criminal trial - there was probably no effort to trace the calls and reconstruct what conversations he was having on the plane.
There is no doubt in my mind that he committed the murders. Given that fact - how likely is a guy with OJ's I.Q. to have planned and executed the perfect crime? Not likely at all. There had to be details to be cleaned up, evidence to be disposed of - and the number of calls that he made, and the time that he was making these air-phone calls (all after midnight west coast time) suggests he was giving direction to Cowlings to tidy some things up and to lose certain implements or accessories used in he crime.
If a federal prosecution had been contemplated first - it would have led to conviction (on the charges that could yet be lodged) and would almost certainly led to conviction on the CA murder charges, because there would have been a roadmap, a playbook for the LA County DA's to follow - created by the much more competent U.S. Attorney's office. Federal prosecutors would never have botched that case the was Marcia Clark did.
Judge Ito did his part too.
Is it too late for a Federal Case - Civil Liberties and all that?
Simpson's acquittal in California state court does not preempt a federal prosecution, given that California and the U.S. are "separate sovereigns"; jeopardy did not attach for prosecutions by the feds or a state other than California.