It’s not surprising that its residents so readily describe Santa Barbara as paradise. On a fertile plain between steeply rising mountains and a sandy, south-facing stretch of the California coast, the city basks in year-round warm sunshine. I was there at the end of January, when the contrast with the wintry chill of London was especially pleasant. It’s generally an easy-going sort of place, Santa Barbara, its large student population sustaining a thriving downtown of trendy cafes and, strikingly, no less than two hat shops – the kind of hat shops that cater to hipsters rather than old men.

But the appearance of paradise doesn’t mean that harmony reigns. Southern California has long been politically polarized; and in an elegant palm-tree fringed plaza I met two people who represented starkly different visions not only of what America should be, but also of its past.

One was John, who, with his American flag, his bullhorn and a car trunk full of copies of the US constitution, had joined a group of around 50 people gathered on the steps of the Spanish-colonial style Santa Barbara News Press building. They were there to support that newspaper’s strident opposition to a new state law that gives limited rights (such as the ability to apply for a drivers’ licence) to ‘undocumented’ migrants – in other words people who have crossed the Mexican border illegally.

This was a national security issue, John told me. “If you come here illegally, you’re an invader,” he said. And it was the duty of the US government to repel invaders. John, a veteran of the US armed forces now in his seventies, had come to California with his parents in 1948. He now feels like he lives in a different place. “It’s a whole lot different from how it was then”, he said. Not only was the government – “Disneyland on the Potomac” as he called it – taxing too much (John wants to abolish the Internal Revenue Service), but the very idea of a nation that upheld the laws was under threat. The tolerance—even celebration, as he saw it — of illegal immigration made a mockery of the laws and undermined the American Dream. Defending illegal immigration was tantamount to advocating anarchy.

John was a member of the local chapter of the Tea Party. Others were there from the Minuteman project, a controversial group that tries to enforce the Mexican border. The lead organisers of the protest was a group based in Claremont called We The People Rising, a reference to the opening words of the US Constitution. Robin Hvidston, a leader of We The People Rising, explained in an articulate and earnest manner that she wanted politicians to recognise the severity of the problems facing US citizens — homelessness and low wages — before giving breaks to people who had not followed the rules in coming into the country. The group was overwhelmingly white and middle aged, but not exclusively — there were Hispanics there too, and an African American man spoke about the murder of his son by a Mexican in the country illegally. They framed their protest as about free speech — someone had sprayed graffiti outside the the Santa Barbara News-Press offices attacking the paper’s use of the term “illegals” to describe undocumented migrants (“The Border is illegal not the people who cross it!”). Quick to link a bloke with a spray can to the murderous attack on the offices of Charlie Hebdo in Paris (“it was on the same day!”), We The People Rising and their allies presented themselves as the defenders of honest, straight-talking, and the free speech protected in the Constitution against the threats both from “ilegals” and “political correctness”. Members of the group were keen to talk not only about the failure of politicians to listen to the people “they work for” but the “lies” and “propaganda” of the “media”.

On the other side of the plaza was a somewhat larger group of demonstrators who had come to support the rights of undocumented migrants and to oppose the line taken by the News-Press. Organised by a local civil rights group It was a much younger much more ethnically diverse crowd on that side of the yellow plastic fence police erected to keep the two groups apart. It had the feel of a student union protest — not surprisingly since many there were from the local University of California campus. They chanted “We are beautiful”, held up placards saying “No Justice, No Peace”, and, to me their most striking image was a picture of a Native American with the words “You’re against illegal immigration? Splendid. When do you leave?” They were also protesting about free speech, they said, making a distinction between free speech and hate speech. And they made much of the fact that the anti-immigration groups had chosen Martin Luther King Day to stage their protest. One man performed the I Have a Dream speech from memory and with an astonishingly good capture of King’s Baptist preacher cadences.

Many wore homemade cardboard butterfly wings, symbolising the Monarch butterfly which migrates freely — across borders — up and down the west coast of North America.

One of those with wings was Dora. Like John, she came to California when she was young. But Dora came illegally, at the age of 19, without any family, to look for work. Echoing millions of immigrants to America over the centuries, she told me that she had come to look for a better life and to work really hard. To do so took bravery and determination, evading not only US border guards but enduring abuse from the Mexican people smugglers she had paid. “I spent all night running” she said. And “so many people stayed behind me. Many die.” “I don’t see see any difference between immigrants”, legal or illegal, she told me. “This is a multicultural country made up for people from all over the world. Dora wants to go to college and to be given “the opportunity to help this country.” Did she think of herself as a Californian, I asked her? Yes she did. And then she talked about the history of the state before it was annexed to the USA in the 1840s, as a province of Mexico, a Spanish colony and, before that, as native American land. “Everyone here is an immigrant.”

Nearly fifty years ago, Richard Nixon, who grew up in Southern California, won two presidential election victories by claiming to speak on behalf of the ‘silent majority’ – men and women who, like Robin today, felt that they had lost their voice in a country that was changing around them.

Well they’re not silent now, but nor, it seems, are they a majority.

Back in 1994, a state ballot initiative was passed attempting to prohibit illegal immigrants from accessing any state services, including education. No one thinks such a measure would have any chance today.

In contrast a new law came into effect on January 1 allowing migrants in the country illegally the right to a California drivers’ licence and to become state registered professionals – lawyers for example.

Were they winning, I asked one of John’s co-protestors?

A pause.

“No, but I don’t see what I can do but keep on fighting.”People were indignant about being accused of racism (“they don’t know me! how can they say that!” one man said).

This post is a version of an piece I did for From Our Own Correspondent on BBC Radio 4