Stephen Prothero's argument in American Jesus is that Jesus is, in America, something of a cipher. Since he is "the many that nobody hates," since he is such an American institution due to the power of American revivalism, every group has a take on Jesus: Christians, Black Muslims, Jews, Hindus, Buddhists, Mormons, and so on. Part of conforming to America is finding a place for, and a version of, Jesus. He is a mirror, a cipher for ourselves and every group that calls America home.
I think the same argument can be made for the Apostle Paul, but with a bit of nuance. Paul has been the upholder of slavery (decreeing that slaves be obedient in Ephesians, or that Onesimus should return to Philemon), the imposer of laws (that women should not speak in church, or should not cut their hair), the dogmatician who develops a theology of the cross, the Apostate Jew who includes the Gentiles in the Christian religion and disregards the law. Paul is often a whipping boy for those who want to uphold a vision of a righteous, humble, and moral Jesus; instead, Paul is the systematizer who turns Jesus into a religion. Paul introduces the Christ, ending the religion of Jesus and replacing it with the religion about Jesus; in him, the Proclaimer is the Proclaimed. For all those who dislike rules and laws, Paul is the enemy to Jesus who taught a gentle spirit of the law.
Much of this is simply unfair to Paul, though. His radical mind was steeped in Judaism and apocalypticism, and his vision of a united church of Jew and Gentile is breathtaking and egalitarian, especially in Galatians. His radical message of grace and acceptance shows he is not a systematizer but someone who introduces a new and perhaps inevitable theme to Christianity. Yet he refuses to allow for a complete antinomianism and quietism, as he instructs about appropriate behavior and ethics. HIs vision is a gospel that frees and a church that is unified in Christ (not the law or Jewish tradition). His is the gospel matured and distilled.
Like the Biblical Jesus, we would do well to read the Biblical Paul, instead of making him into the cipher for our own hopes, fears, dreams, and despairs.