Conservatives in Louisiana view the nomination of Robert F. Kennedy Jr. as a litmus test for President Trump's agenda.

Robert F. Kennedy Jr. goes before two two U.S. Senate hearings in his quest to head the nation's health department. Louisiana Sen. Bill Cassidy, a doctor, sits on both.

Click in for more news from The Hill{beacon} Health Care Health Care   The Big Story All eyes on Cassidy for second RFK Jr. hearing Sen. Bill Cassidy (R-La.), chair of the Senate

Caroline Kennedy said in a scathing letter about her cousin, Robert F. Kennedy Jr., that she felt "an obligation to speak out."

Cassidy is expected to challenge RFK Jr. on his vaccine skepticism and views on public health in today's confirmation hearing.

Mr. Kennedy appears to have most Republicans behind him as he seeks the job of health secretary, though he couldn’t escape his past stances on vaccines and abortion.

Robert F. Kennedy Jr. has said vaccines are not safe. His support for abortion access has made conservatives uncomfortable.

The health committee chairman, Sen. Bill Cassidy, R-La., also has expressed concerns about Kennedy's anti-vaccine work. A physician, Cassidy said earlier this month he “had a frank conversation” and “spoke about vaccines at length” with Kennedy. On Tuesday, Cassidy told reporters that he is still unsure if he is backing Trump’s nominee.

In a contentious confirmation hearing to become the nation’s top health official, Robert F. Kennedy Jr. struggled Wednesday to answer questions about Medicare and Medicaid, programs that affect tens of millions of Americans,

RFK Jr. claimed he is not “anti-vaccine” and appeared unfamiliar with key aspects of healthcare insurance programs in his confirmation hearing.

Some GOP senators want public commitments from Robert F. Kennedy Jr. before deciding whether to support him as the next secretary of the Department of Health and Human Services, signaling that President Donald Trump’s pick will have to win over uncertain Republicans in order to secure the job.