Until George W. Bush was President, I don't think any Republicans had noticed Social Security's Chief Actuary, Stephen Goss, who has just retired. He was holding a technical, non-political job. He started work for Social Security in 1973 and had been the Chief Actuary since 2001. Actuaries can argue among themselves about issues around the edge of their profession but the numbers are the numbers. It should matter little which competent person holds the position.
You may remember that W. wanted to privatize Social Security. W. would have preferred it if Goss had supported that effort. The problem was that W. never really had a plan to privatize Social Security. He inherited a lot including an ancestral Republican hatred of Social Security but hating it doesn't mean you have a plan to replace it with something better. Instead of a plan, all W. had was a certainty that Social Security was terrible and that there had to be some way to privatize it that would be much better and that they'd figure out a plan later. It was impossible for Goss to do what W. wanted -- score W.'s plan to privatize Social Security in a way that helped advance the plan. In fact, it was impossible for him to score it at all since there never was a plan. In any case, Goss never regarded making recommendations on significant policy proposals to be part of his job duties, much less shading the numbers to help or hurt a President's preferred policy proposals.
Do we really want to replace a widely respected non-partisan actuary with someone who fudges the numbers to help the current Administration?