More than ever, it was clear that last weekend’s massacres in El Paso, Texas, and Dayton, Ohio, had put Trump on the defensive and added fierce new urgency to Democratic efforts to engineer his ouster. Trump has not accounted for the echoes of his own rhetoric about immigrants and minorities in the manifesto composed by the anti-immigrant gunman in Texas, and he has appeared far more focused on feuding with his critics than on striking a tone of healing.

Former Vice President Joe Biden, in one of the most fiery speeches of his campaign so far, argued Wednesday that Trump had both explicitly and implicitly “fanned the flames of white supremacy in this nation” with his language.

“Trump readily, eagerly attacks Islamic terrorism but can barely bring himself to use the words ‘white supremacy,’” Biden said in Burlington, Iowa. “And even when he says it, he doesn’t appear to believe it. He seems more concerned about losing their votes than beating back this hateful ideology.”

Speaking in Charleston at Emanuel African Methodist Episcopal Church, where a white supremacist gunman killed nine black worshippers in 2015, Sen. Cory Booker of New Jersey also blamed Trump for encouraging hatred. The weekend’s violence, he said, was “sowed by those who spoke the same words the El Paso murderer did, warning of an ‘invasion,’” a word Trump has used to describe migrants approaching the Southern border.

And in El Paso, former Rep. Beto O’Rourke, who hails from the city, criticized the president shortly before his visit. “We live in a country where we have a president who demonizes communities like this one, who vilifies immigrants, who says that those from Mexico are rapists and criminals, and warns of invasions and infestations,” he said. O’Rourke also told MSNBC that he believed Trump was a white supremacist.

Trump has emphatically denied that he is racist, and on Wednesday, he dismissed reporters’ questions about the role of his rhetoric in dividing the country, saying his language “brings people together.”

The extraordinary focus this week on white nationalism, gun violence and domestic terror appeared to reframe a chaotic presidential campaign as a searing moral debate about the racial history and cultural destiny of the United States. Trump, who rose to power railing against the country’s changing ethnic and cultural texture, contends that Democrats should be punished for opposing his immigration policies and rejecting the values of the rural white people who make up his base.

Democrats, meanwhile, are now arguing in the most explicit terms yet that white supremacists are receiving aid and comfort from the president. Where Democrats differ, it is largely over whether Trump is the country’s chief affliction, or a symptom of deeper woes.

But if the starkest contrast this week has been between Trump and those vying to unseat him, the speeches Wednesday by several Democratic candidates also exposed important gradations in their worldviews. Booker spoke at considerable length on racism as an American heritage, while Biden discussed dark episodes from the past but leaned more heavily on nostalgia and triumphalism.

In Iowa, Biden acknowledged that American history was no “fairy-tale.” “I wish I could say that this all began with Donald Trump and will end with him,” he said. “But it didn’t and I won’t.”

But Biden also assailed Trump as representing a wild departure from the American political tradition, blaming him for stoking hatred and abandoning the unifying role past presidents have sought to play. He contrasted Trump’s ambivalent response to racism and tragedy with the conduct of his predecessors, including Bill Clinton’s response to the Oklahoma City bombing in 1995 and George W. Bush’s visit to a mosque after the terrorist attacks of Sept. 11, 2001.

In a biting one-liner that has become a regular jab on the campaign trail, Biden said that Trump had “more in common with George Wallace than he does with George Washington.”

Speaking from the pulpit at the church known as Mother Emanuel, one floor above the room where the 2015 massacre took place, Booker eschewed that kind of nostalgia for the Founding Fathers in his own speech against violent racism.

Booker said instead that white supremacy had been “ingrained in our politics since our founding,” within the text of the Declaration of Independence and the Constitution. The present moment, he said, demanded both federal action to regulate guns and investigate white nationalists and a cleareyed confrontation of the past.

“Racist violence has always been part of the American story, never more so than in times of transition and times of rapid social change,” Booker said, linking the trauma of the last week to slavery and segregation, and “demagogues throughout generations who stoked racist and anti-immigrant hatred, often for votes, and then enshrined their bigotry into laws.”

Booker neither mentioned Trump by name, nor did he cast the president as an aberrational figure in American history, as Biden did. Instead, he urged a broad moral reckoning over racism and departed from his prepared remarks to call, in an echo of the Rev. Martin Luther King Jr., for the rise of a “generation that truly will be free at last.”

“There is no neutrality in this fight,” he said. “You are either an agent of justice or you are contributing to the problem.”

The speech by Booker, one of two leading black candidates for the Democratic nomination, had the potential to be one of the most important moments of his campaign, testing his power as a voice of moral clarity and racial justice after a week of national pain.

He has lagged in the polls, insisting on a message of healing that has at times clashed with his party’s prevailing mood of hot indignation. But after months of toiling away in relative obscurity he had a standout performance in the second round of Democratic debates last week, besting Biden in a series of exchanges on race and criminal justice and displaying for a national audience the kind of sunny pugilism that has made him a force in New Jersey and in the Senate.

Few venues for Booker’s message could have been as laden with symbolism as the one he chose. A funeral for the victims of the massacre, by a gunman who has since been sentenced to die, became the site of one of the most memorable moments of former President Barack Obama’s time in office. During the ceremony, he broke into a rendition of “Amazing Grace” and called both for the removal of the Confederate flag from South Carolina’s capitol building and a remedy to “the mayhem that gun violence inflicts upon this nation.”

Booker earned applause and murmurs of appreciation throughout his speech, including with a prominent quotation from “our beloved Toni Morrison,” the Nobel laureate who died this week. Borrowing her words, Booker said: “The function of freedom is to free someone else.”

Deirdre McClain, who watched Booker speak from the pews, said she found his remarks moving and persuasive, including his recitation of the names of the nine people murdered in the church.

“I was surprised at how he made the past come to the present, how he knew the names of those who had passed in this very church and that he connected it to freedom,” said McClain, 53. “That resonated with me.”

McClain said Booker was among several candidates she was considering in the presidential race, along with Sens. Kamala Harris of California and Elizabeth Warren of Massachusetts, and Biden.

Biden leads in national polls and maintains a strong advantage with African-Americans, most importantly in South Carolina, the first Southern state to cast its votes for the nomination. Biden has spent much of the summer relitigating his decadeslong record, but he is often at his strongest when casting the race as a choice between himself and Trump.

Biden and Booker have had plenty of company in their condemnations of Trump this week. The candidates have been all but unanimous in their descriptions of the president as a racist or as bearing some personal responsibility for the violence in El Paso.

Trump has long attacked Latin American migrants as dangerous criminals and his campaign has run thousands of digital advertisements describing illegal immigration as an invasion. He has spent much of the summer insulting prominent black and Hispanic Democrats, deriding the predominantly black city of Baltimore and addressing a rally where his supporters engaged in a chant of “send her back” directed at a Democratic lawmaker, Rep. Ilhan Omar of Minnesota, who is a naturalized citizen who came to the United States as a child refugee from Somalia.

Though Trump denounced white supremacy in his speech from the White House on Monday morning, he has continued to batter his political rivals in divisive terms, railing on Twitter against O’Rourke, who has described Trump this week as an obvious racist. Trump mocked O’Rourke for taking “Beto” as a nickname — his birth name is Robert — tweeting that it was a “phony name to indicate Hispanic heritage.”

Speaking Wednesday at an El Paso park, O’Rourke praised his hometown as a safe, beautiful and welcoming place made stronger by its binationalism and the immigrants and asylum-seekers who live there.

“Though we bore the brunt of this hatred and this racism and this intolerance and this violence, I believe this community also holds the answer,” he said. “The way that we welcome one another and see our differences — not as disqualifying or dangerous, but as a very source of our strength, as a foundation of our success — that needs to be the example to the United States of America today.”

This article originally appeared in The New York Times.