Trump is trying to divide us, but it's backfiring. We are One Nation.

Who is American?

Not Muslims. Not people of Mexican heritage. Not according to Donald Trump.

Trump critics respond: Defining Americanness in racial and ethnic terms is unprecedented and a radical departure for the United States.

History weighs in: Wrong. Trump's targeting of Mexicans, Muslims and other people of color is an old American story.

Here's where I weigh in: Today's champions of a Rainbow America are an exception in the long course of American history, but Trump has picked a fight he is losing. I'm a sucker for history's ironic turns, and 2016 has brought us a doozy: Trump's attacks on Muslims, Mexicans and others appears to be solidifying a more inclusive America.

A new school year is upon us, so let's start with a familiar routine — reciting the Pledge of Allegiance. Written 125 years ago, the pledge invites us to declare our loyalty to "one Nation … indivisible."

At first blush, the devotion to One Nation enjoys widespread and enduring acceptance. Abraham Lincoln famously anticipated the Civil War by proclaiming that a "house divided against itself cannot stand." And the Civil War did keep the nation's territories from splitting apart, though at a monstrous human toll.

But how can One Nation be indivisible in a diverse country with a bounty of distinct ethnic communities?

Let's circle back to Trump.

For generations, groups of white Americans equated an indivisible One Nation with homogeneity. As Republican House Leader Kevin McCarthy put it, "America isn't divided by race, religion or gender."

Through much of our history, a host of rotating tactics were used to enforce the idea of a homogenous One Nation. Assimilation and the metaphorical "melting pot" were hopes.

The most persistent approach has been the harshest: Keep out unwanted nationalities.

In a development that we may soon see repeated, the rough Know Nothing edges were sanded down and cemented in highly restrictive immigration laws over the ensuing decades. The Chinese were barred. In 1888, the Supreme Court signed off on this exclusion as a form of self-protection — "the presence of foreigners of a different race … who will not assimilate with us [is] … dangerous."

Congress did not stop there. Into the 1920s and beyond, it continued and tightened restrictions on immigrants based on their national origins. Whites from Britain were welcome; people of color were not. Trump is an extension of this history in America.

Since the mid-1960s, new immigration laws opened America's doors to growing numbers of people from around the world. Immigration rose from 265,000 in 1960 to about 1 million annually by the 1990s. The foreign-born population grew from about 5 percent in the mid-1960s to nearly 14 percent now.

As more people of color entered the U.S. and raised families, movements for civil rights converted the idea of One Nation into an affirmation of equal rights. The language of exclusion has been replaced by demands for inclusion in sharing America's bounty and equal opportunity for women and people of color without regard to sexual orientation.

Social and economic disparities have become a marker of injustice — a violation of what it means to live in One Nation. In the mid-1960s, President Lyndon Johnson commissioned the Kerner Report to dissect the causes of inner-city violence. The unsparing findings remain painfully familiar — "Two societies, one black, one white — separate and unequal."

Some of the most articulate and widely read writers today reveal the false promise of One Nation. National Book Award winner Ta-Nehisi Coates points to two societies — one of them is protected by a "safety net of schools, government-backed home loans, and ancestral wealth," while African-Americans experience the "club of criminal justice." Claudia Rankine's literary gem, "Citizen," points to the "medical term — John Henryism — for people exposed to stresses stemming from racism."

The embrace of an inclusive America is a mainstream value today. These are the values taught our children and embraced by millennials.

Businesses battle to win over consumers in America's diverse communities. They know the profit margins in appealing to the tastes of blacks, Hispanics and Muslims. And firms know their future rests on recruiting the best talent in a diverse workforce.

Trump has been a Pied Piper for a dated America that seeks to revive the Know Nothing ethos. He speaks for the 4 out of 10 whites who think that racism against them is as big a problem as it is against people of color, despite reams of data that document contrary patterns in employment, criminal justice and more.

But here's what may be the monumental irony of 2016: The greatest success of nativists in generations may end up as their Waterloo.

Deathbed conversion — Trump is now undergoing the political equivalent. Scrambling to avoid a bleak outcome in November, he is clumsily appealing to the women and voters of color that he has spent a year offending.

What about Hillary Clinton?

Disgust with Trump is not tantamount to an embrace of Clinton.

This year's election might be described as an unpopularity contest. Clinton's popularity ratings are the second-lowest ever for a major-party nominee — Trump's are the lowest. The media feeding frenzy over her health and her private e-mail server are further sinking her reputation for honesty.

On the issue of race, Clinton has been harshly criticized for her past support of her husband's policies that produced the mass incarceration of young black men.

Alluding to our separate paths to America, Bush put a stake into the Know Nothings by proclaiming that "we have never been held together by blood or background." Instead, he placed us all in a community defined by tolerance for our differences: "At our best, we practice empathy, imagining ourselves in the lives and circumstances of others. … At our best, we honor the image of God we see in one another. ... At our best, we know we have one country, one future, one destiny."

Obama situated the Dallas sniper's targeting of white officers within America's divisive battles over race and acknowledged that it exposed the "deepest fault lines of our democracy." But the president insisted that we are not "as divided as we seem." Departing from his reluctance to spotlight his race and heritage, he gave witness to the America striving to be inclusive. "I know [about] that because of … what I've experienced in my own life, what I've seen of this country and its people — their goodness and decency."

The rising notion of America as a multiracial nation is a process — not an endpoint. The anger and resentment that Trump has distilled won't disappear. Substantial numbers of the white working class and poor see a rigged system and, in truth, they have been abandoned by both political parties with few opportunities to move ahead. They remain a reservoir of frustration; Trump tapped it, and others will, too.

What's different is that the balance of power appears to have decisively shifted. The coming challenge is how we build One Nation that is truly inclusive.