I study constitutional history, not US history, and my focus is more on British Empire / Commonwealth than the US, so bear with me. I'm sure the moderators will slap my wrist if this isn't good enough.

The US constitution was written at a time when modern representative democracy was still in its infancy. In particular, no one knew how to make a presidential system work - it had never been done before.

The British system, which was still a universal point of reference at the time of the War of Independence, was in a state of flux, with the king's role diminishing (and that of the Prime Minister and Cabinet rising), but not clearly defined. When people spoke of 'the executive' in Britain in the 1770s/80s, they were still referring to the King, even if it was increasingly the case that the king was bound and limited to a fairly considerable extent by ministerial advice.

There were precedents and examples from the State constitutions, but these too were quite new and untried, and often unsatisfactory. Many of those early state constitutions had a very weak governor who was indirectly elected by the state legislature, sometimes assisted and advised by a Privy Council. also chosen by the legislature. In other words, they were arguably closer in some respects to a parliamentary than a presidential system.

So it wasn't clear from the beginning of the US constitution just how the new presidential executive was going to work. This was especially so, because the founders were skeptical, or even actively hostile, to political parties. There was a sense in which they expected the President to be a sort of quasi-monarch, a detached supervisor, overseeing the cabinet but not actively leading the policy agenda.

This all reached a head with two questions. Firstly, whether a president could dismiss as well as appoint members of the Cabinet, and secondly whether those Cabinet secretaries could sit in the Congress to improve co-ordination and co-operation between the branches of government. These points are not clearly articulated in the US Constitution. At stake was the issue of how effectively the President could act as a policy leader, and not simply as a 'chief administrator'.

The Confederate constitution resolved these ambiguities, expressly allowing the President to dismiss cabinet members and diplomatic representatives, while giving a rudimentary security to tenure to other executive branch officials. It allowed Congress to provide by law for cabinet members to sit and speak in Congress (but not vote) and to answer questions relating to their departments - a foreshadowing of the kind of quasi-parliamentary arrangement later proposed by Woodrow Wilson.

These are just two examples of how the CSA constitution tried to build upon and fix some of the issues in the US constitution, as those issues were understood by the political elite of the South at the time.

Another change was to the president's tenure of office - from a then constitutionally unlimited number of four year terms (although Washington had set a strong precedent of a two term maximum) to a single, six-year term.

For those interested in how constitutions develop over time, and how 'daughter' constitutions reflect on going debates in 'parent' constitutions, the CSA constitution is very interesting.

Perhaps what's most interesting about the CSA is that it did not really emphasise states' rights. In fact, it diminished states rights in so far as it prohibited states from passing anti-slavery laws. It is almost as if the whole 'states' rights' thing was a bit of a smoke screen.

Constitutions often have a theme, a tone, that runs through them - a sort of overall vision of what the Constitution is trying to achieve, or avoid. It is very clear from the text of the CSA constitution that its main focus was on entrenching slavery, and that other reforms to the system of government - while interesting, and perhaps even beneficial - were entirely secondary to that objective.