I would point to Galatians 2:7-9,
On the contrary, when they saw that I had been entrusted with the gospel to the uncircumcised, just as Peter had been entrusted with the gospel to the circumcised (for he who worked through Peter for his apostolic ministry to the circumcised worked also through me for mine to the Gentiles), and when James and Cephas and John, who seemed to be pillars, perceived the grace that was given to me, they gave the right hand of fellowship to Barnabas and me, that we should go to the Gentiles and they to the circumcised.
This looks to me like a spirit of unity and mutual honor. Paul is saying that there existed a mission to the circumcised and to the uncircumcised, to Jews and to Gentiles, and that when the apostles met to discuss the gospel and their mission, they recognized in each other the same work of God.
What evidence is there of a power struggle between Paul and James?