Shifting timelines for two Affordable Care Act stabilization bills championed by Sen. Susan Collins are raising alarms that the bills could stall out and die. But Maine’s senior senator is insisting that she has commitments for passage of the bills from President Trump and key Republican leaders. The bills may be delayed further into 2018 as Congress considers many issues. Collins, a moderate Republican, had emphasized the passage of the two ACA bills to secure her vote for the $1.5 trillion tax reform package because it included the repeal of the ACA’s individual mandate, which will undermine health insurance markets.