CORALVILLE, Iowa — Bernie Sanders on Saturday unleashed his most forceful rebuke yet of Michael R. Bloomberg’s potential presidential bid, warning the former mayor of New York that he would not be able to “buy this election” and chastising his plan to skip campaigning in the early states.
Speaking at a rally in Coralville, near the liberal home of the University of Iowa, Mr. Sanders, the senator from Vermont, repeatedly addressed Mr. Bloomberg by name, almost daring him to enter a Democratic primary race that has already been in progress for months.
“Our campaign is going to end the grotesque level of income and wealth inequality which exists in America today,” said Mr. Sanders, who was joined by Representative Alexandria Ocasio-Cortez, a standard-bearer of the progressive left. “So tonight we say to Michael Bloomberg and other billionaires: Sorry, you ain’t going to buy this election.”
He also derided Mr. Bloomberg’s intended strategy of bypassing the key early voting states where so many of the current candidates are devoting time, money and resources.
“You’re not going to get elected president by avoiding Iowa, by avoiding New Hampshire, South Carolina and Nevada,” Mr. Sanders said. “You’re not going to buy this election by spending hundreds of millions of dollars on media in California. Those days are gone.”
Mr. Bloomberg on Friday took the first step toward a candidacy, filing paperwork to qualify for the ballot in Alabama. His looming entry into the race has underscored its fluidity while presenting the threat of a centrist competitor to former Vice President Joseph R. Biden Jr.
As a leading progressive, Mr. Sanders could potentially benefit from a Bloomberg candidacy that siphoned voters from Mr. Biden. But Mr. Sanders displayed no eagerness to see Mr. Bloomberg in the race, and was quick to draw a direct contrast between their efforts, saying his campaign had the grass-roots support to win rather than billions of dollars in the bank.
“Bloomberg can have his billions,” he said, “but that is why we are going to win this election.”
The rally was Mr. Sanders’s second public event of the day with Ms. Ocasio-Cortez of New York, who joined him on Friday for a two-day swing through the first-in-the-nation caucus state. During a rally in Council Bluffs on Friday, both progressive politicians largely avoided making any references to Mr. Bloomberg.
Mr. Bloomberg’s early moves, and his suggestion that he would follow the unconventional campaign strategy of skipping all four traditional early-state contests and instead stake his candidacy on delegate-rich primary states like California and Texas, has supplied fresh fodder for candidates like Mr. Sanders and Senator Elizabeth Warren of Massachusetts, who are both campaigning on anti-elitist, progressive messages.
Earlier in the day on Saturday, at a climate change forum in Des Moines, Mr. Sanders directed a more glancing blow at Mr. Bloomberg, saying the country needed “a dynamic democracy — a democracy where all of us play a role in shaping public policy, not some billionaire who decides that he wants to run for president of the United States because he’s a billionaire.”
Mr. Sanders also took a shot at Mr. Biden, who recently said he would be willing to accept support from a super PAC; his campaign, Mr. Sanders said, had no such financial vehicle.