Sen. Kamala Harris wasted no time in attacking President Trump in her introduction on Wednesday afternoon as Joe Biden’s running mate.

Harris spoke for the first time since Biden selected her to be the first Black woman and first Asian American on a major-party ticket on Tuesday. She presented what she called an “open and shut” case against Trump and Vice President Mike Pence for their mishandling of the coronavirus pandemic.

“This virus has impacted almost every country, but there is a reason it has hit America worse than any other advanced nation,” she said. “It’s because of Trump’s failure to take it seriously from the start.”

Biden and Harris spoke to a mostly empty gymnasium at Alexis I. duPont High School in Wilmington, Del., in the highest profile moment of the campaign since Biden wrapped up the Democratic nomination in March. Both walked to the podium wearing masks, and Harris sat at a distance from Biden while he gave his introduction.

Biden noted that Trump had attacked Harris as “nasty” following Tuesday’s announcement.

“Is anyone surprised Donald Trump has a problem with a strong woman?” Biden asked.

Biden also took note of the historic nature of his selection, saying that Black and Brown girls would take inspiration from Harris.

“Today just maybe they’re seeing themselves in a new way as the stuff of presidents and vice presidents,” he said.

In her address, Harris said she was proud to stand with Biden, and gave a nod to some of her critics who had suggested she was too “ambitious” to play the number-two role.

Harris said she was “mindful of all the heroic and ambitious women before me, whose sacrifice, determination and resilience makes my presence here today even possible.”

During her own campaign for president, Harris vowed to “prosecute the case” against Trump. In her speech she picked up where she left off when she dropped out in December, attacking Trump for fumbling the crisis.

“Trump pushed miracle cures he saw on Fox News,” she said. “He said the virus would ‘poof’ go away, like a miracle. When other countries opened back up for business, what did we do? We had to shut down again.”

She also went after Trump’s economic record, saying he had inherited a growing economy from President Obama.

“Like everything else he inherited, he ran it straight into the ground,” she said.