The American Constitution creates three branches of government and ensures that there will be sufficiently great amounts of ideological diversity among these branches of government. Despite this regime ensuring external heterogeneity, the American system, uniquely among the world's major constitutional democracies, rarely creates the same degree of heterogeneity at the highest levels of the Executive Branch that it does among the highest levels of the various branches of government. This Article discusses the distinctiveness of the homogeneous high-level American Executive Branch and the events that led to such a situation. At the first key moment defining the separation of powers in the new American Constitution, the time of the creation of the Constitution, there was still support for an Executive Branch composed of a diverse range of leaders, and the rules of the new Constitution did not hinder this ambition. At the second key moment defining the separation of powers in the new Constitution, the creation of the Twelfth Amendment in 1804, a series of new rules and the political and legal realities that followed resulted in the highest levels of the Executive Branch becoming far more homogeneous than the one that preceded the Twelfth Amendment.
When Democratic President Barack Obama ran for the presidency in 2008, he promised to appoint members of both political parties to his cabinet if he became President.1 After his election, President Obama retained Republican President George W. Bush's Secretary of Defense, Robert Gates,2 appointed as his Secretary of Transportation former Republican member of the House of Representatives Ray LaHood,3 and tried (unsuccessfully) to appoint as his Secretary of Commerce Republican Senator Judd Gregg of New Hampshire.4 Obama's decision to retain Secretary Gates and to appoint Secretary LaHood means that Republicans5 will be overseeing two of the major areas of policy activity for the Obama Administration: Secretary Gates will oversee the withdrawal of American forces from Iraq and the intensification of American efforts in Afghanistan,6 and Secretary LaHood will oversee the billions of dollars of infrastructure spending that are part of President Obama's stimulus package.7 The current situation - in which two members of the party that lost the last election for President hold high-ranking executive office - is rare in the United States, even though it is common at the highest levels of most of the world's other major constitutional democracies.8
Why is this so? Why are the central players (who are the focus of this Article, rather than the entire Executive Branch) in the American Executive Branch so homogeneous, in terms of partisanship and therefore also usually in terms of ideological positions? There are many kinds of explanations for this homogeneity. Part of it may have to do with the way we view elections and our desire to give the party that wins elections control of the branch that they won. Part of it may have to do with our distinctively political rather than bureaucratic idea of executing the laws.
But part of the explanation of the internally homogeneous American Executive Branch is historical and has to do with a centrally important - but generally misunderstood and ignored - constitutional transformation: the transformation that followed the enactment of the Twelfth Amendment in 1804. After the American presidential election of 1800, in which a close election resulted in the House of Representatives choosing Thomas Jefferson as President and the Senate choosing Aaron Burr as his Vice President,9 the Twelfth Amendment was added to the Constitution to change the rules used to select the President and Vice President of the United States. Before the Twelfth Amendment, electors cast ballots for two individuals, without identifying which particular office they wanted those individuals to hold, and the person finishing in second place nationally (if they had a certain minimum number of electoral votes) became Vice President. …