To what extent does the creation of the regulatory administrative agencies such as the IRS, FCC, FDA, EPA, OSHA, and the Federal Reserve Board challenge the idea of the President as a chief executive?  What can be done to ensure the legitimacy of regulatory agencies?

Sources to consider:

    a    The Constitution of 1787, especially Article I section 8, and Article II sections 2-3
    b    Marini, John. The Politics of Budget Control: Congress, the Presidency, and the Growth of the Administrative State. Washington, Philadelphia & London: Crane Russak/Taylor & Francis, 1992.