The executive presidency was actually introduced by the Second Amendment to the 1972 Constitution soon after the 1977 general election, but the full presidential state was established a few months later with the promulgation of the 1978 Constitution. Presidentialism represented a radical departure from the models of executive collegiality that had hitherto characterized the constitutional forms of Ceylon and Sri Lanka since the introduction of universal electoral democracy in 1931. Under diarchic executive under the 1931 Constitution was a quasi-Cabinet, which was meant to train local politicians in operating the Westminster system, which in turn was introduced by the 1946-8 Constitution and was continued when the country became a republic. Presidentialism had no precedent in the modern constitutional tradition of the country, and therefore it was culturally legitimated by reference to the much older political tradition of the ancient Sinhala-Buddhist monarch. The monarchical presidency has since come to dominate both institutional relations within Sri Lanka’s system of government, as well as the landscape of electoral politics more broadly, and it has under some Presidents further eroded the republican character of the polity. As a result, ever since its introduction, there has been vigorous debate about the adverse consequences of executive presidentialism from the perspectives of both democracy and pluralism.
The fundamental and therefore most visible change to the structure that occurs with the new relationships brought about with the introduction of Presidentialism is the access the upper level has directly from outside. The presidency which was hitherto a small institution represented in the structure on a modest scale is enlarged to reach the very edges of the lower building and in fact overwhelming it with roof structure that come out to shelter the access stairs to the upper level from outside. The process of expansion also compromises the judiciary, the roof of which requires some changes. The access to the judiciary from the presidency is also made grander with a new staircase which partly hinders the direct access provided to the people.
With the executive power being changed to be headed by the presidency, stronger links between the spaces housing executive power on the lower level are made through corner staircases and outer corridors, accessing these without going through the main legislative chamber. This new access way reduces the transparency of the legislature and thus governance itself. The added weight is made without recourse to any structural changes to the existing building.
The outer appearance of the building continues with the style and form of the previous structure, simply by expanding the upper level. This makes the whole appear to be one unitary structure dominated by the upper level with its extended roofs and grand staircases. The lower level structure disappears into insignificance in this new scheme of things.