I am struck by the simplicity of solutions for what are otherwise complex problems. But problems are made "complex" because the "simple" solutions are too difficult. They are simple, but not easy.
So two senior leaders who inherently distrust each other's motives can be the source of relatively pervasive paralysis for a global company, making an impact of hundreds of millions of dollars (if not more) and hundreds of thousands of lives. Yet "complex" solutions involve "managing around" this chronic dysfunction.
There are only three simple solutions:
get rid of both of them,
get rid of one of them (assuming the remaining person has healthy relationships otherwise), or
invest time in getting them aligned and ideally give them something significant they simply have to deliver together.
Return-on-energy and likelihood of success must be considered here. But decide, and act...and let the complexity be in the execution not in the decision. Most times we know which of three such options are called for...we must just be leaders enough to act accordingly.