Bipartisan resistance from Massachusetts party leadership forms the central factor holding the all-party primary measure near even odds ahead of the November 3 vote. Both the Democratic and Republican state committees oppose the shift from separate partisan primaries to a single ballot advancing the top two candidates regardless of affiliation, citing risks of reduced party influence, greater donor sway, and altered general-election dynamics in a heavily Democratic state. Reform advocates, including some moderate legislators and former officials, counter that the change could boost primary turnout and competition. Recent voter guides and endorsements from lawmakers and unions underscore the divide, while the absence of decisive polling leaves room for late shifts from turnout patterns or additional spending.