President-elect Trump's selection of Mehmet Oz, or Dr. Oz, to lead CMS adds to the uncertainty over the future of Medicare, Medicaid and the Affordable Care Act, Victoria and Peter report.

Why it matters: If confirmed by the Senate, the former TV doctor and failed Pennsylvania Senate candidate will take charge of a federal agency that provides coverage to more than 160 million people.

The big picture: As with some of his other picks, Trump is elevating someone with no prior experience in government to run an agency whose programs and policies touch virtually every segment of the health system.

What they're saying: In a post on Truth Social, Trump said he was selecting Oz to work with RFK Jr. to "take on the illness industrial complex."

• He added that Oz will also "cut waste and fraud within our country's most expensive government agency, which is a third of our nation's healthcare spend and a quarter of our entire national budget."

Republican senators on Tuesday seemed supportive of the Oz nomination.

• Incoming Senate HELP Chair Bill Cassidy posted on X that he was "glad to hear @DrOz has been nominated for CMS administrator," since "it has been over a decade since a physician has been at the helm of CMS."
• Sen. John Barrasso told Axios that Oz is "a world class physician, surely he understands how Medicare and Medicaid works … It's a scenario where he has significant knowledge and would be able to make improvements in the system."

Sen. John Fetterman, who defeated Oz, wrote on X: "If Dr. Oz is about protecting and preserving Medicare and Medicaid, I'm voting for the dude."

• But top House Energy and Commerce Democrat Frank Pallone said he was alarmed that Trump turned to "a TV celebrity without the experience or background to lead [CMS]. Unfortunately, this nomination further demonstrates that Trump is not concerned about Americans' health care."

Health interest groups were more muted. The Federation of American Hospitals congratulated Oz and said it looks forward to working with him to advance health outcomes and "protect 24/7 patient care."

Flashback: During his time as a Senate candidate, Oz said that addressing health care costs would be the first item on his agenda if elected.

• He also supported banning abortions, with exceptions for saving the life of the mother, but also echoed Trump's stance that the issue should be left to the states.
• When Oz had his own TV show, he drew criticism from some in the scientific community for pushing alternative therapies like fad diets.
• During the pandemic, he also promoted hydroxychloroquine as beneficial in the treatment of COVID.

Before jumping into the 2022 Pennsylvania Senate race, Oz had expressed his support for the Affordable Care Act and health insurance mandates, which he thought were important to ensure everyone had health care coverage.

• When asked about his stance on the ACA during the Senate campaign, a spokesperson for Oz said he wouldn't have voted to pass the health care law, and that he "does not support a big government takeover of the health insurance industry."

The bottom line: With HHS secretary-designate Robert F. Kennedy's views on Medicare or other payment policies unclear, the CMS administrator could have wide discretion to enact policies.

• And since Trump has been big on saying he doesn't want to cut Medicare benefits, one big focus will be on Medicaid.
• Oz would be in a position to grant waiver requests from conservative-led states intent on reshaping Medicaid, including imposing work requirements on recipients, which is something the first Trump administration tried to do.