Ms Pelosi said the US is also seeing risks challenging the principles of democracy, including free and fair elections and the independence of the judiciary.
She was speaking at the residence of the US ambassador to Ireland, in Dublin’s Phoenix Park, on Sunday, as she became the inaugural recipient of the Fulbright Ireland Public Service Award.
The Fulbright Commission is an educational exchange programme operated through a bilateral partnership of the US state department and the Irish Department of Foreign Affairs.
Earlier, Ms Pelosi met President Michael D Higgins at nearby Aras an Uachtarain.
President of Ireland Michael D Higgins with former speaker of the US House of Representatives, Nancy Pelosi (Maxwells/PA)
On Sunday, she said the US administration is concerned about China’s influence, as well as climate change and the war in Ukraine.
“Big picture, we’re in a competition between autocracy and democracy – have no doubt that that fight is on,” she said.
She said this manifests itself in several ways, for example “brutal force” by Russia and commercial efforts by China for autocracy to “buy itself in”.
Ms Pelosi said the US is also seeing risks challenging the principles of democracy, including free and fair elections and the independence of the judiciary.
She added: “Democracy is at stake, and I don’t say that lightly.”
In a wide-ranging “fireside chat” with US ambassador to Ireland Claire Cronin, the long-serving Democrat reflected on her career and dealings with former presidents.
Running through a series of anecdotes, she said she got along very well with George HW Bush but criticised his relationship with China after the Tiananmen Square massacre.
She recalled another incident, years later, when his son George W Bush was president.
“I’m talking to the president, who is a sweetheart, George Herbert Walker Bush, and we’re talking about family and so on and he says ‘madam speaker, will you give my kid a break?’.”
She said the younger Bush was a “lovely” man but “not when it came to the war in Iraq”.
Former speaker of the US house of representatives Nancy Pelosi (Brian Lawless/PA)
On Bill Clinton, she said he was a “wonderful president who does not get the credit he deserves”.
However, she said the Democrat president was also “terrible on China”.
Saying she was a firm believer in bipartisanship, Ms Pelosi added that she often quoted one of Ronald Reagan’s final presidential speeches, in which he said America’s “pre-eminent” position in the world was because of its openness to talent from other countries.
She said that Barack Obama was “spectacular” on policy areas like healthcare.
Ms Pelosi, who made several references to Donald Trump without naming her political rival, said: “There are some people who should never be allowed anywhere near the White House.”
She said current president Joe Biden “really knows his stuff”, adding: “He just has a clear vision for our country. He has more experience than anybody.”
Ms Pelosi said she was “certain” he would be re-elected.