Maine’s senior senator has been seen as a pivotal swing vote on the president’s Cabinet nominees, though she has rarely broken rank thus far.

The Republican said she received several assurances from Robert F. Kennedy Jr. on vaccines, although many public health organizations strongly opposed his nomination because of his legacy of questioning the safety and efficacy of vaccines.

Kennedy Jr. cleared a procedural vote in the Senate Wednesday that fell along party lines, teeing up the confirmation. Maine Republican Senator Susan Collins announced earlier this week she would vote to confirm RFK Jr.