DES MOINES, Iowa — Former Vice President Joe Biden and Montana Gov. Steve Bullock opened the Iowa State Fair’s 2020 presidential blitz on Thursday by blistering President Trump and promising to push new gun restrictions.

“I believe everything the president’s said and done encourages white supremacists,” Biden said as Trump continued to take criticism for his handling of back-to-back mass shootings. One of the shooters is believed to have written a racist screed echoing some of Trump’s incendiary language about immigrants.

Bullock said Trump’s rhetoric and behavior — attacking his critics on the day he traveled to ostensibly console victims’ families in El Paso, Texas, and Dayton, Ohio — are beneath the office he holds.

“The lies and the statements that divide us by race, gender, geography — we expect more out of our preschoolers now than we do the president of the United States,” Bullock said.

Biden and Bullock are the first of more than 20 candidates — nearly all Democrats — who will speak at the Iowa fairgrounds over the coming days. It’s a rite of passage for would-be presidents, and for Democrats it highlights their challenges in a state like Iowa, a presidential battleground that mixes cultural conservatives and farm country, liberal college towns and plenty of swing voters in between.

California Sen. Kamala Harris on Thursday declined to label Trump a white supremacist, as former Texas Rep. Beto O’Rourke has since the El Paso shooting.

“I think that there’s no question that his words and his language ... (have) been about condoning the conduct and certainly accommodating the conduct of white supremacists,” Harris told reporters after a campaign stop at a private college in Sioux City, Iowa. “So, I think it’s a fair conversation to have.”

Pressed on the question, she said, “‘I think you should ask him that question.”

Biden accused Trump on Wednesday of “fanning the flames of white supremacy.”

Trump won Iowa comfortably in 2016 after Barack Obama, with Biden as his running mate, won the state twice. The typical Democratic caucus electorate, meanwhile, leans far more liberal than the general electorate.

Biden and Bullock promised to compete both for caucus votes and for the state in November.

“If we can’t win back places we lost ... if we can’t give people a reason to vote for us and not just against him, Donald Trump will win again,” Bullock said. “The path to victory doesn’t just go through the coasts.”

The two candidates Thursday reaffirmed their support for new gun restrictions including expanded background checks, and bans on certain military-style weapons and ammunition.

By Bill Barrow is an Associated Press writer.