The former Democratic candidate did not rule out returning to politics in a veiled attack aimed at US President Donald Trump.
Terry Gross on National Public Radio (NPR)asked Mrs Clinton: “I want to get back to the question, would you completely rule out questioning the legitimacy of this election if we learn that the Russian interference in the election is even deeper than we know now?”
She replied: “No. I would not. I would say.”
Mr Gross replied: “You’re not going to rule it out.”
And, Mrs Clinton again said: “No, I wouldn’t rule it out.”
Republican Mr Trump won the election in a surprise victory with 304 electoral votes compared to Mrs Clinton’s 207 last November.
The United States Intelligence Community has concluded with high confidence the Russian government interfered in the 2016 US presidential election.
An allegation Russia and Mr Trump’s administration have denied.
Mrs Clinton said: “I am fundamentally optimistic about our country, but I am not naive, and I don’t think we can change things unless we take it seriously.”
And Mrs Clinton said with Donald Trump in charge, she now fears for the future of the United States.
She said: “I believe that Donald Trump poses a clear and present danger to our democracy, to our institutions, to the rule of law, to the civil rights and human rights of so many Americans, to the economic distribution of wealth.”
Mrs Clinton said she believes the Trump campaign communicated with the Russians during the campaign trail.
She said: “We know that the intelligence community of our country — people who I’ve worked with, people who I have every bit of confidence in — have concluded that this came from the top of the Kremlin and was intended to help Trump.”
The former presidential candidate added the US voting system of the Electoral Collage should be abolished.
She said: “I was sitting listening to a report on the French election and the French political analyst said, “You know in our country the person with the most votes wins, unlike in yours.”
Special counsel Robert Mueller is currently leading an investigation into any links between the Trump campaign and Russia and Congress is also investigating Russia’s meddling in the election.