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 on Wednesday morning he appeared far more focused on feuding with his critics in the Democratic Party and the media 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 that Trump had “fanned the flames of white supremacy in this nation” with both explicit and implicit language as president.

“Trump readily, eagerly attacks Islamic terrorism but can barely bring himself to use the words ‘white supremacy,’” Biden said Wednesday afternoon 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, South Carolina, 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.

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.”

For both Trump and his Democratic challengers, the extraordinary focus this week on white nationalism, gun violence and domestic terror appeared to reframe a chaotic presidential campaign — at least temporarily — 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 political base. Democrats, meanwhile, are now arguing in the most explicit terms yet that white supremacists are receiving aid and comfort from the president of the United States.

“His low-energy, vacant-eyed mouthing of the words written for him condemning white supremacists this week I don’t believe fooled anyone, at home or abroad,” Biden said, referring to Trump’s remarks Monday about the El Paso shooting.

There is virtually no disagreement among the Democratic candidates about Trump’s character, or his culpability in what they see as a still-unfurling disaster of race relations and social cohesion. Where they 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 on 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 acknowledged dark episodes from the past but leaned more heavily on nostalgia and triumphalism. Booker neither mentioned Trump by name, nor did he cast the president as an aberrational figure in American history, as Biden did.

In Iowa, Biden acknowledged that American history is “not a 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 he 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.

Insistently branding Trump as a figure who offends the nation’s political values, Biden contrasted the president’s ambivalent response to racism and tragedy with the conduct of his predecessors — Bill Clinton’s soothing response to the 1995 bombing at a federal building in Oklahoma City, for instance, and George W. Bush’s visit to a mosque after the terror attacks of Sept. 11, 2001.

In a biting one-liner that has become a regular jab on the campaign trail, Biden said to applause 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.

He 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, as well as a clear-eyed confrontation with the American 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 the roots of 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 urged a broad moral reckoning over racism and departed from his prepared remarks to call, in an echo of 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 in a crowded race that has largely focused so far on debates about economic inequality. He has been lagging in the polls, insisting on a message of national healing that has at times clashed with his party’s prevailing mood of hot indignation.

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 for his crimes, 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 for a remedy to “the mayhem that gun violence inflicts upon this nation.”

There may have been some political risk involved for Booker in delivering his speech from a place so freighted with history. Some Democrats believe he has suffered in the 2020 campaign, fairly or not, from voters’ instinct to measure him in their minds against the example of Obama.

But this week of national pain has developed into a vitally important one for Booker, who after months of toiling away in relative obscurity has begun to show signs of breaking through. 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.

Booker earned several bursts of applause and murmurs of appreciation throughout his speech in Charleston, including with a prominent quotation from “our beloved Toni Morrison,” the Nobel laureate who died this week. Borrowing her words, before a modest audience of six or seven dozen people clustered at the front of the church, Booker said: “The function of freedom is to free someone else.”

Deirdre McClain, who watched Booker speak from the pews Wednesday morning, said she found his remarks moving and persuasive in their linkage of the American past with the bloodshed of the present, including with his invocation of Morrison and a recitation of the names of the nine people murdered in the church four years ago.

“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, a database administrator. “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 continues to hold the lead in national polls and has maintained a strong advantage with African Americans, most importantly in South Carolina, the first Southern state to cast its votes for the Democratic nomination. Biden has spent much of the summer relitigating his decades-long record, but he is often at his strongest when casting the race as a choice between himself and Trump, something he sought to do in his speech in Iowa.

Trump has done little to blunt criticism from Democrats and even some conservatives since the weekend. On Monday morning, he delivered a statement from the White House deploring the violence and denouncing white supremacy. But he has also continued to batter his political rivals in divisive terms, railing on Twitter on Wednesday morning against former Rep. Beto O’Rourke of Texas, who hails from El Paso and 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.”

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. The president has spent much of the last month insulting prominent black and Hispanic Democrats on Twitter, 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.

Biden and Booker have had plenty of company in their condemnations of Trump this week. The Democratic presidential 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.

Several candidates, including Mayor Pete Buttigieg of South Bend, Indiana, and Gov. Jay Inslee of Washington state, have unveiled new policy proposals for addressing white nationalist extremism. Others, like Harris and Warren, have been trumpeting pledges they have made in the past to crack down on dangerous firearms and take on the gun lobby, led by the National Rifle Association.

This article originally appeared in The New York Times.