"...to demonstrate at the present time His righteousness, that He might be just and the justifier of the one who has faith in Jesus." (Romans 3:26)
For many years I was taught and believed that Saint Paul's epistle to the Romans was his systematic treatise on the doctrine of salvation. It is about "how" the "righteousness of God" is applied to His people and how they should behave because of it...
While the doctrine of salvation is clearly held forth in Romans, I have come to believe that Paul's focus on the "righteousness of God" is more about who God is than how we are saved. Paul wrote that he was "not ashamed of the gospel of Christ," because it justifies God in an utterly fallen world (Romans 3:25,26).
Think about it. Wherever Paul preached in the ancient world, people thought he was crazy. Jews saw the cross as a stumbling block and Gentiles saw the incarnation as foolishness (1 Cor 1:23). It didn't resonate with his audience so he found himself arguing that Christ makes sense of God in a world full of death, evil, and suffering. Paul was not ashamed of the gospel of Christ, because it alone reveals that God is righteous and faithful to a fallen world. God is not removed from our peril, but enters into it because He is good. There is a real sense in which Romans is a theodicy - a wrestling with the problem of evil. Romans is Paul's apologetic for the justification of God.
We do not lose anything approaching Romans in this way. In fact, we gain a fresh appreciation for the God who saves because He is righteous. Along with Paul, we are confident that the Gospel is good news for the world, not just for me as an individual. The greatest apolgetic for the Gospel is not presuppositionalism or evidentialism, but Jesus Himself. Yes, the world is full of evil, but God is dealing with that personally in Jesus Christ. He resurrects His people, Jew and Gentile, in Jesus Christ. He is restoring the creation through Jesus Christ. In the gospel of Jesus Christ, God is justified.