Key parts of the Senate budget proposal containing major elements of former President Donald Trump’s legislative agenda are at risk, with more provisions potentially being cut. The main obstacle is not a lack of GOP support or Democratic opposition, but rulings by Senate Parliamentarian Elizabeth MacDonough, an unelected official appointed in 2012. She determines what can be included under the Senate’s budget reconciliation rules, which allow passing bills with a simple majority, bypassing the 60-vote filibuster. On Thursday, MacDonough advised Senate Republicans to remove several banking and environmental provisions from their budget plan. She blocked efforts to roll back a Biden-era electric vehicle mandate and to cut funding for the Consumer Financial Protection Bureau (CFPB), a federal agency created to regulate financial services. These rulings reflect her role as the de facto referee on Senate rules.

Senate Majority Leader John Thune is pushing to pass the bill quickly, but any provision ruled ineligible under reconciliation will require 60 votes to pass, giving Democrats blocking power. Senate Democrats have challenged parts of the GOP plan, arguing they violate reconciliation rules that require direct budgetary impact. MacDonough’s rulings have sided with Democrats on several points, frustrating Republicans. Among blocked items are cuts to CFPB funding and repealing Biden’s EPA regulation mandating that 67% of new cars be electric or hybrid by 2032. She has yet to rule on major proposals like a permanent extension of Trump’s 2017 tax cuts. Trump has urged Congress to pass the bill before July 4.