The fundamental idea of the United States is that people of different races, religions, backgrounds and identities can prosper together, making a greater whole out of a bunch of different parts.

You can fit a lot of different points of view into such a big country. But one has no place at all: The false and toxic sentiment that it belongs to one group over everybody else.

Time and again, by many different names, white supremacy surfaces from the background to tear at the seams that hold the country together. We are in one of those moments.

A racist and anti-immigrant movement is once more gaining momentum, and as the Maine Sunday Telegram reported last week, it is growing in Maine.

They have held rallies in Portland and Lewiston, the two most diverse communities in the state, yelling racist and homophobic slurs. They unfurled a banner reading “Defend white communities” over a highway, hung up racist fliers, and sent racist literature to elected officials of color.

A prominent neo-Nazi even has bought land in northern Maine in order to build a whites-only community — at least the second person to come to our state with that idea in mind.

There has been an uptick in white supremacist propaganda not only in Maine and New England but across the country as hate groups grow in number and size. It’s not a surprise that hate crimes and other activity meant to harm and intimidate minorities are on the rise. White supremacists are now the nation’s top domestic terror threat, an FBI spokesperson told the Telegram.

It’s appalling that racist, nativist and anti-Semitic groups feel so comfortable spreading their hate in public, using tactics meant to intimidate their targets and make them feel less safe in their communities.

And it’s disgusting how much their efforts have become intertwined with today’s Republican Party.

You can trace the party’s new relationship with the far right at least back to the Unite the Right rally in Charlottesville, Virginia, in which hate groups marched with torches and yelled neo-Nazi slogans in protest of the removal of Confederate soldier statues.

Rather than forcefully denouncing the march, then-President Trump minimized it, even mimicking their talking points as he placed blame on “both sides.”

There are no two sides here. There are those who believe in the fundamental idea of America, and those who think that people like themselves should be held up above all others. Only one of those works in a country like ours; the presence of the other inevitably leads to conflict.

Buoyed by Trump’s support, the hate groups have become more vocal and public in their efforts to spread the word of white supremacy. At the same time, mainstream Republicans have embraced the energy these groups provide.

As a result, the views espoused by white supremacists, which have for years been relegated to the periphery of the Republican Party, are now something close to mainstream among conservatives.

It’s no longer disqualifying for a Republican to socialize with neo-Nazis and anti-Semites, or attend their conferences, or share their articles; in fact, candidates seek out their attention. Tucker Carlson of Fox News became by the highest-rated cable show in the country by attracting conservative viewers with the Great Replacement conspiracy theory, which says that liberals are actively trying to steal the power reserved for white people.

Just last week, an aide to Florida Gov. Ron DeSantis’ presidential campaign resigned after creating and sharing a pro-DeSantis video using Nazi imagery, after the campaign had earlier put out a homophobic ad. DeSantis, of course, has made anti-Black and anti-LGBTQ policies the center of his campaign — and he’s not alone in the GOP.

It’s a sickness, and it’s spreading. We cannot afford to dismiss it or downplay it.

As experts told the Telegram, it’s a dangerous time. Everyone that’s able should recognize the danger, and everyone who believes in the fundamental idea of America should stand up for it.