The Canadian Senate is often the target of criticism and there have been countless calls to reform Canada’s upper chamber since its creation in 1867. While much has been written about the Senate’s lacklustre performance in the modern period, there remains limited discussion on the operation of the Senate during its early years. Addressing this lacuna is important, in order to consider whether the Senate ever performed as those who designed the institution had intended. This thesis analyzes the original intentions for the Canadian Senate, developed by the Fathers of Confederation and specified in the British North America Act (1867), showing how the architects of the Senate regarded it as a chamber for sober second thought. The thesis then considers the extent to which senators followed the founders’ intentions when legislating over three government bills that were blocked in the Senate during the first sixty years of its existence. Drawing on Hansard, newspaper articles and archival documents, the thesis examines the operation of the Senate with regard to debating and then blocking the Esquimalt and Nanaimo Railway Bill (1875), the Naval Aid Bill (1912) and the Old Age Pension Bill (1926). These blocked bills provide a representative sample of the diverse bills considered by the Senate in its first sixty years. When considered together they also encompass the different federal political party contexts which occurred in the Canadian Parliament within the first sixty years of Confederation. The thesis demonstrates that although the senators provided a well informed, critical second thought when debating these bills, the issue of partisan block voting that had concerned the Fathers of Confederation and remains a significant aspect of contemporary debates about Senate reform, affected the independence of the Senate and the legislative outcomes in each case. The thesis suggests that although the Senate can provide a sober second thought on legislation, the ideal Senate, as envisaged by its creators, is always likely to be affected by the dynamics of partisan politics. Those involved in the creation of second chambers, or proposing Senate reform in the contemporary period, may benefit from the broader historical perspective that this thesis provides. In making a broader contribution to debates about the design of second chambers, this thesis highlights how the objectives of those involved in the initial design of second chambers may not be easily achieved in practice, even after scrupulous deliberations prior to a second chamber’s establishment.