The federal government is not a healthy organization. Its goals are diffuse, its priorities are overlapping and contradictory, and its efforts are scattershot. It spends enormous amounts of money, but fails to deliver on its promises, time and time again.
The best legacy you could leave for the country is to right-size and re-focus the federal bureaucracy. Make the government competent again, and you will help everyone for generations to come, regardless of our politics.
A simple, repeatable plan is best. The job of righting the ship of state will take much longer than one term, or even many terms. I suggest cycles of Pruning and Planting.
For one year, focus on pruning the organization, especially the regulations which are used to justify headcount. Anything that is outside the core mission of each agency will be the target. The goal is to cut out the deadwood, and prune away the things which are draining the organization.
In the next year, focus on doing new projects. This is how you test how well your pruning worked. A leaner organization should be meaner. Re-allocate resources within the agencies to work on things which serve the core mission. Focus like a laser beam on doing the job and doing it better than the private sector.
Now repeat this process until the federal government is competent. No doubt it will take many cycles. Your job as the first is to lay the groundwork and start the trend.
By doing this, you will attract the very best talent the country has to offer. High performing people don't work primarily for the money, they work to make an impact. This is what the Elon Musks of the world understand.
In short, do the job of a chief executive. Your promise must be to make it so the government can execute any mission given to it by the legislature with excellence. Yours is not a policy-setting office, it is tactical and logistical.
A well-run, high-functioning administration should be your core mission, not politics. Leave the politics to the talkers. You've got something that needs to be built.