Final answer:
Lack of bipartisan support best explains why Hillary Clinton's healthcare reform failed, as it faced significant opposition from Republicans and even dissension within the Democratic Party, leading to its defeat in Congress.
Step-by-step explanation:
The position that best explains why Hillary Clinton's healthcare reform failed is a) Lack of bipartisan support. The healthcare initiative proposed by the Clinton administration in 1994, often referred to as 'Hillarycare,' faced significant opposition in Congress. Despite initial backing from various institutions, the political climate shifted as Republicans recognized the strategic advantages of opposing the reform. This opposition was bolstered by the introduction of the 'Contract with America' by Newt Gingrich and the Republican Party, which gained traction and led to significant Republican gains in the mid-term elections. Additionally, the healthcare plan faced internal dissent within the Democratic Party, public skepticism fueled by negative advertising from interest groups, and accusations of bureaucratic expansion and government overreach, epitomized by the characterization of the plan as an unwarranted expansion of federal power. These factors collectively led to the demise of the proposed healthcare bill.