Named to lead the nation's sprawling Department of Health and Human Services, Robert F. Kennedy Jr. has big ideas for busting public health policy norms.

His Senate confirmation hearings -- should they happen -- will come with lots of questions about what Kennedy's ideas would look like in practice.

His new role would mean relinquishing his outsider critic status and working from within a massive government system, leading an agency of 80,000 employees and dealing with everything from drug approvals to food recalls to the pandemic response.

So, what happens when his motto "Make America Healthy Again" collides with one of Washington's largest government bureaucracies?

"He seems very clear on what it is he wants to get done. I'm just not sure he has an understanding of what it will take to get that done," said one former senior HHS official who worked in the Biden administration.

Vaccines

On vaccines, President-elect Donald Trump's picks of Johns Hopkins University professor Marty Makary to lead the Food and Drug Administration, former GOP Rep. Dave Weldon to head the Centers for Disease Control and Prevention and Dr. Janette Nesheiwat as surgeon general certainly add to Kennedy's ability to make changes -- if they're confirmed by the Senate.

Both Makary and Weldon have raised questions about vaccine side effects, although they've also at times been supportive overall of the role vaccines play in public health. Kennedy himself has falsely claimed that vaccines cause autism, which has been debunked by numerous studies.

In their new positions, Makary, Weldon and Kennedy would have the power to select the experts who sit on important FDA and CDC advisory panels. Those panels play a key role in vaccine recommendations and authorizations for the general public, ultimately creating public health guidance for years to come.

"I think massively, in large part, the health care community would continue to move forward on vaccines as they do now, as they are considered to be one of the massive successes of public health in the last 100 years. And I don't think that would change," said Tom Inglesby, a former senior adviser to HHS and the White House during COVID-19 during the Biden administration.

"But what could change is potentially the cost of vaccines, the access to vaccines, guidance around new vaccines that might come online, and also confusion around public messaging from the federal government about safety and effectiveness of vaccines," Inglesby said.

Food and nutrition

When it comes to chemicals and the food Americans consume, it's less clear how Kennedy could make changes at HHS, as opposed to the Environmental Protection Agency or the Department of Agriculture, which have more oversight of areas such as water fluoridation, which Kennedy opposes, or school lunches, which he says he wants to make healthier. He has said, however, that he would gut the entire nutrition department at the FDA.

Kennedy could also move around funding -- he's said he'd deprioritize infectious disease research in favor of chronic illness research, for example. As avian flu cases continue to rise -- raising concerns about a new pandemic -- public health experts and former government officials have pushed back strongly on that idea.

But he has also called for restrictions on food additives, dyes and ultra-processed foods, something he could have direct influence over through the FDA, which determines safe thresholds for the "Acceptable Daily Intake" on substances.

Kennedy has generally received a more cautious welcome from the public health community regarding his focus on healthy food.

"There are some things here that are worth working on. You know, if we're looking at the school lunch program in America, 30 million children get more than half of their calories from that program. It would be a wonderful thing to make that the best school lunch program possible," said Dr. Richard Besser, former CDC acting director.

But many public health experts are also wary of giving Kennedy credit, for fear it could lend credibility to other false information he promotes. He advocates drinking raw milk, for example, even though the pasteurization process kills off bacteria that can cause serious illness, including the fast-spreading avian flu.

"One of the dangerous things about RFK Jr. is that there are bits of things he says that are true, and they're mixed in. And it makes it really hard to sort out what things you should follow because they're based on fact, and which things are not," Besser told ABC News, where he was former chief health and medical editor.

Experts also question Kennedy's ability to counter powerful Washington lobbies -- one of his stated main goals -- in a Trump administration focused on working with big business on deregulating industries.

Abortion access

Another area where Kennedy could be out of line with the Trump administration is abortion access. Kennedy has said he supports legal abortion access until fetal viability (despite an earlier comment on the campaign trail that he later walked back about supporting a 15-week ban) and that such decisions should be up to women.

Many abortion rights advocates still expect the Trump administration to quickly move to rescind protections and halt legal fights the Biden administration initiated after the fall of Roe v. Wade -- but are hopeful that Kennedy and the broader administration would not attempt sweeping bans.

"[Trump's] obviously waffled on this and other issues a thousand times so I'm not going to trust every word he says, but I do think there's the possibility that he and his administration has seen that actually, abortion access is very popular," said Katie O'Connor, senior director of abortion policy at the National Women's Law Center.

"We have seen that over the past three elections, and there could be pushback if this administration does something to further restrict abortion access."

There are certainly members of Trump's orbit who would support broader restrictions on abortion, but Trump himself has said he would not sign a federal ban if Congress passed one.

Some of the policies O'Connor expects to see rolled back would include the Pentagon paying for service members who need to cross state lines to get an abortion because of where they were stationed, as well as expanded access to abortion pills through telemedicine.

As HHS secretary, Kennedy could undo these rules and also build on the first Trump administration's efforts. He could expand protections for health care providers who don't want to perform abortion procedures, allowing more providers to deny care, and make it more difficult for private insurers to cover abortion, leaving it more expensive for patients, O'Connor said.

Large-scale bans, were they executed, would focus on removing access to the medication abortion pill called mifepristone, either by attempting to take medication abortion off the market by way of the FDA approval process, or employing a very old law called the Comstock Act to prohibit the pills from being mailed.

"I do hold out hope that this administration doesn't want to expand political capital on abortion," O'Connor said.