What is the main obstacle that must be overcome to make two light nuclei fuse together?

1. Both nuclei approaching each other carry positive charge from their protons. 2. The Coulomb repulsion between these positive charges is the major obstacle that must be overcome for fusion to occur. 3. Enough kinetic energy, often supplied by extreme heat, is needed to push the nuclei close enough for the short-range strong force to take over. 4. A shortage of neutrons is not the described obstacle, and magnetic attraction would pull nuclei together, not apart. 5. Absorbing visible light is unrelated to the fusion process. 6. So Coulomb repulsion between the nuclei is correct. _Source: OpenStax Physics (CC BY 4.0), Ch 22 "The Atom", section 22.4 Nuclear Fission and Fusion_