What analogy does Les use to explain the transition in the Book of Acts?

Les teaches that the Book of Acts is a transition period, and he illustrates it with a political analogy: moving from one presidential administration to another, specifically Jimmy Carter's administration to Ronald Reagan's. These were two totally different sets of ideas, yet both operated under the same Constitution. He points out that after Reagan won the election in November, until inauguration day, Washington was not passing a bunch of laws and nothing was really accomplished; everything came to a standstill until the transition from one administration to the other was made. Les says the same thing happened in the Book of Acts: you are moving from that Jewish program of temple worship, the Law, and Jesus as the Christ, the King, the Redeemer of Israel, over to Paul's Gospel of grace through faith plus nothing. He asks whether this is a contradiction, and answers no—it is a change of program. Coming back to his two political administrations, he notes they did not have to change the Constitution; Carter operated under the same Constitution Reagan did. Therefore, he says, always take into account that you don't use the Book of Acts for a doctrinal Book, because you will get thrown a curve almost every time. Instead you come into Paul's letters, which is what follows the word "but" in verse 26.