What is the argument for a retrial on a charge of first-degree murder?

With this statutory and constitutional foundation laid, defendants begin constructing their syllogistic argument by relying on the general proposition that the double jeopardy clause "protects against a second prosecution for the same offense after conviction." (North Carolina v. Pearce (1969) 395 U.S. 711, 717, 89 S.Ct. 2072, 2076, 23 L.Ed.2d 656.) They then insist that the felony murder and the underlying robbery are the same offense because they are necessarily based upon the same facts. Defendants therefore conclude that retrial on the felony murder violates the prohibition against double jeopardy.