But he shouldn't expect a warm welcome from progressives, even if he sometimes sounds identical to many of them.
For some, Kennedy's shared beliefs merely offer a foot in the door. Others have already slammed that door altogether.
Senator Peter Welch, a Vermont Democrat, said Kennedy has "rejected science" but he sees alignment with Kennedy in a few areas -- "food additives, healthy eating, exercise. His acknowledgement we're getting ripped off in prescription drug prices."
But asked if he'd consider supporting Kennedy, Welch said, "I'm gonna listen. I mean, I really do like his focus on clean food and getting additives out."
Likewise, Kennedy's corporate-skeptical rhetoric can sound not too distant from Senator Elizabeth Warren's own sometimes, but it's not enough to to override her other concerns.
"It's all important, but we can't sacrifice the lives of children because they don't get their measles vaccine, because the head of HHS is caught in some conspiracy theory that is antiscience," Warren said.
Kennedy's antivaccine outlook is the first concern Democrats typically bring up when asked about his nomination, but it's far from the only one on their minds.
Senator Ed Markey, who quickly made clear last month that he would not vote to confirm Kennedy, listed a number of his past positions -- from questioning whether HIV causes AIDS or whether antidepressants cause mass shootings -- to argue he has "disqualified himself" to serve.
"The fact that Robert Kennedy may be correct on one public health issue does not excuse his being wrong on many public health issues," said Markey, who serves as top Democrat on the Senate Health, Education, Labor, and Pensions Committee's subpanel on health care.
Kennedy will not need Democratic votes to be confirmed if he wins the support of all but three Republican senators. The flip side of Kennedy's overlap with Democrats is that unanimous GOP support is not guaranteed.
Some Republicans, for instance, are uneasy about the former Democrat's past support of abortion access, a realm where the Department of Health and Human Services has significant influence. His diatribes against the food and agriculture industry, meanwhile, have sparked real concern among Republican senators from major farming states.
Notably, a pair of influential Republicans could provide stiff pushback to Kennedy's antivaccine views. Senator Bill Cassidy, a Louisiana Republican, chairs the Senate's health panel; he is a physician who has advocated for the safety and efficacy of vaccines, including COVID. And Senator Mitch McConnell, the Kentucky Republican who just stepped down as Senate GOP leader, is a survivor of polio.
On Friday, The New York Times reported that a top Kennedy adviser had petitioned the Food and Drug Administration to revoke approval for the polio vaccine. Hours later, McConnell issued a statement castigating the move. "Anyone seeking the Senate's consent to serve in the incoming administration would do well to steer clear of even the appearance of association with such efforts," McConnell said.
Still, the most vociferous pushback to Kennedy will come from Democrats. Thanks to his prominence within the party's most famous political family, and his lifelong activism on certain topics, Kennedy will see familiar faces asking tough questions on Capitol Hill: many senators know him personally. Markey, for instance, said he worked "for decades" with Kennedy on climate issues.
Senator Richard Blumenthal, a Connecticut Democrat, worked closely with Kennedy in the 1990s when he was attorney general of Connecticut and Kennedy was active in his legal advocacy group that filed lawsuits to eliminate water pollution in Long Island Sound and the Hudson River.
"I had enormous respect for his work on the environment, that's what we worked on together," Blumenthal said. "But I haven't talked to him for maybe 15 years, I'm guessing."
Still, Blumenthal isn't inclined to back Kennedy. "I would have trouble supporting him if he continues to take the kind of stands that have been reported on vaccines, measles, mumps, rubella," he said. "To oppose children having those vaccines, I think strikes me as wrong for the secretary of health and human services of the United States of America."
For Democrats who are open at all to considering Kennedy, the reason is his tough criticism of food industry companies. He has argued that Washington has allowed them to foment a chronic disease epidemic by pushing unhealthy and addictive products with minimal checks or oversight. He has expressed support for banning or limiting food dyes that have been scrutinized for health impacts, as well as high fructose corn syrup, the cheap form of sugar prevalent in soft drinks and junk food.
For decades, Democrats have sounded the same notes, and Republicans often responded derisively, dismissing their concerns as liberal nanny-state pipe dreams.
Senator Cory Booker, a New Jersey Democrat, has been among the most vocal liberal critics of the food industry. Last month, Kennedy shared a video Booker posted to X in which the senator criticized food that is "making us sick" and praised Booker's "long history of leadership" on the issue.
Asked about Kennedy, Booker said, "I mean, listen to him when he talks about a lot of aspects of food policy, the chemicals on food, the subsidizing of ultra-processed, sugar-filled foods."
"Those are all areas where you find a lot of his speeches seem like he's lifting from my speeches," Booker said. But he added he "had a lot of concerns on the vaccination and other public health aspects of that job."
Another potentially sympathetic ear is Senator Bernie Sanders, a Vermont Independent who caucuses with Democrat and is the top Democrat on the Senate health committee. Sanders has been a longtime critic of food industry conglomerates; at an early December hearing the committee held on the food industry's role in the obesity epidemic, Sanders' castigation of the FDA aligned closely with Kennedy's views.
Last Thursday, Sanders said he expects to meet with Kennedy soon to discuss the nomination but declined to answer further questions.
There's a sense even among Democrats aligned with Kennedy's views on food and nutrition that the impact he could have on the issue would be limited, given the position he would hold. The agency with the broadest jurisdiction on those food matters is the Department of Agriculture, which administers food assistance programs and sets school lunch standards, among other things.
The Department of Health and Human Services houses the FDA, which regulates what foods and supplements are safe and influences nutrition guidelines. Those are relevant, no doubt, to Kennedy's views, but HHS also oversees the National Institutes of Health and the Centers for Disease Control, areas where Democrats see his conspiratorial views and vaccine doubts having disastrous effect.
"Look, I share some of his views when it comes to healthy foods and trying to make sure that we have more nutritious diets for our kids," said Senator Chris Van Hollen, Democrat from Maryland, which is home to the NIH and FDA. "There are areas of agreement. But, you know, this is the person that would be in charge of the Department of Health and Human Services . . . his position on vaccines is very concerning, because I do think it would put the country's health at risk."