President Barack Obama launched a full-throated defense of open immigration policies Tuesday, hailing it as America's "oldest tradition" amid a fierce election-fueled row over tighter rules.
Hours before Republican candidates held a security-focused final presidential debate of the year, Obama told 31 newly naturalized Americans that fair immigration was the touchstone of their adoptive country.
"Just about every nation in the world, to some extent, accepts immigrants," Obama said. "But there is something unique about America."
Obama -- speaking in the National Archives rotunda, flanked by the U.S. Constitution, Bill of Rights and Declaration of Independence -- said America does not "simply welcome" new arrivals.
"We are born of immigrants, that is who we are, immigration is our origin story."
"For more than two centuries it's remained at the core of our national character, it's our oldest tradition, it's who we are, it's part of what makes us exceptional."
The campaign to succeed Obama has been marked by tough talk against migrants, not least from Republican frontrunner Donald Trump.
The real estate mogul-turned-politician has vowed to ban Muslims from entering the country and to deport illegal migrants from Latin America.
The debate has taken on a rougher edge in the wake of the terror attacks in Paris and California.
The shooting in San Bernardino that killed 14 Americans was carried out by U.S.-born Syed Farook and his Pakistani wife Tashfeen Malik, who arrived in the United States on a fiancee visa.
The White House has agreed to look again at some visa procedures, but insists that refugees in particular are well vetted and have not proven a threat.
Obama -- who himself has lived outside the United States and is the son of a migrant father from Kenya and a mother who lived in Indonesia -- has bristled at efforts to curb the flow of migrants.
"In the Mexican immigrant today, we see the Catholic immigrant of a century ago," he said. "In the Syrian seeking refuge today, we should see the Jewish refugee of World War II."
Listing instances of past discrimination against Japanese, Irish and Italian immigrants, Obama said, "on days like today, we need to resolve to never repeat mistakes like that again."
Officials describing Obama's approach point to parallels between today's boiling immigration debate and the 2014 Ebola outbreak in West Africa.
Then, politicians had clamored to demand a ban on travelers coming from affected areas, while Obama resisted.
"He doesn't give in to the hysteria of the moment," insisted a senior administration official.
That, Obama's allies say, contrasts with Republicans who voted for an increase in refugee admissions after Syrian toddler Aylan al-Kurdi washed up on a Turkish beach, only to reverse course after the Paris attacks.
But with the 2016 election around the corner, Democrats also spot a political opportunity to paint Republicans as anti-immigrant.
With the United States demographically shifting to become less white, Republicans can scarcely risk further alienating minority voters, who currently vote Democrat in droves.
The White House may be quietly hoping that Tuesday's debate brings more stark rhetoric.