New York Mayor Bill de Blasio, who vowed to become national leader for progressives, took his campaign for higher taxes on the rich to America’s heartland and the home of the first presidential test of 2016.

De Blasio, 53, brought the same message to Des Moines, Iowa, that he delivered to New Yorkers a little more than a year ago, when he became the first Democrat in 20 years to run the largest U.S. city. He says income inequality is the defining issue of our time.

“It’s clear that the wealthy among us could sustain higher taxes,” de Blasio said during remarks Thursday to a crowd of about 60 in Drake University’s library, where he was a guest of former U.S. Senator Tom Harkin and the Harkin Institute for Policy and Citizen Engagement. “If we accept the status quo, and if we accept it in particular because we think it’s politically untenable to confront it, we will put ourselves in danger.”

He cited Lloyd Blankfein, chief executive officer of Goldman Sachs Group Inc., who said last year that inequality was “destabilizing.” He also quoted billionaire Warren Buffett, who said of successful investors, “potential taxes have never scared them off.”

De Blasio’s remarks came amid a Midwest swing that included a stop in Nebraska on Wednesday. He arrived in Iowa the same week as former Secretary of State Hillary Clinton, the newly announced candidate and presumptive frontrunner for the Democratic presidential nomination.

De Blasio managed the former first lady’s successful 2000 bid to become a U.S. senator from New York, and in 1997 he worked for the U.S. Department of Housing and Urban Development in her husband’s administration.

No Endorsement

New York’s tabloids made front-page news out of de Blasio’s refusal to endorse Clinton on April 12, the same day she declared that she was in the race. The mayor said he would wait until she supports policies consistent with his agenda.

Clinton joined about nine others as Harkin’s dinner guest at his home Wednesday night, the former Iowa senator said. They didn’t discuss the mayor’s non-endorsement, he told reporters.

“I said I was going to be with Bill de Blasio today and she said, ‘I love Bill de Blasio,’” Harkin said. “She was very high on Bill.”

On “Meet the Press” April 12, de Blasio said of Clinton, “she is one of the most qualified people to ever run for this office, but we need to see the substance.”

De Blasio points out that since the 2008 financial crisis, the wealthiest 1 percent have gobbled up 95 percent of the additional earnings created in the recovery. For the rest, wealth and wages have remained stagnant or worse. Fairness and social cohesion require government to improve conditions for the middle class and poor, he says.

‘National Convener’

He’s pushed the theme since he won the mayoral election in 2013 by 49 percentage points -- the biggest margin ever for a non-incumbent. Weeks before taking office, he announced that the job included his acting as “a national convener” for “a progressive urban agenda” that mirrors what he’s pushed in New York: universal all-day pre-kindergarten, housing subsidies to prevent homelessness, increasing the minimum wage, sick pay and scholarship aid to attend the city’s public universities.

U.K. Trip

De Blasio has since taken his message to the U.K., where he addressed a Labour Party conference in September, and to frequent meetings with mayors in Boston and Washington to seek money for mass transportation, infrastructure maintenance and fewer restrictions on immigration.

It was a coincidence that put de Blasio and Clinton in Iowa the same week. He said he’s planned the trip to Des Moines for months. Iowa will hold caucuses for the 2016 presidential election on Feb. 1.

At a Dairy Queen stand in east Des Moines, Sherri Harper, 42, who is unemployed, ordered a vanilla crunch cone and said she’s never heard de Blasio, yet she wasn’t surprised the mayor of New York would be in town.

“There’s always politicians coming to Iowa,” she said.

The mayor also addressed students at the University of Nebraska on Wednesday night. He told them he came from a city where an apartment recently sold for “a jaw-dropping $100 million” and another rented for $500,000 a month.

“At the same time that those at the top are doing so well, 46 percent of New Yorkers -– nearly half our city -– is living at or near the poverty level,” he said.

DeBlasio hosted an April 2 meeting at Gracie Mansion, his official Manhattan residence, that included Connecticut Governor Dannel Malloy; former Governor Ted Strickland and U.S. Senator Sherrod Brown, both of Ohio; and Jonathan Soros, son of the billionaire hedge fund founder and philanthropist George Soros.

New Contract

They emerged pledging to create a new “contract with America” to draw 2016’s presidential candidates to their agenda. The pact would push to tax the rich to pay for job- creating infrastructure improvements and help for families struggling to pay for education and housing, he said.

While Democrats have consensus around social issues, a divide remains on the economy between the “Wall Street wing of the party” and a more populist side, said Katrina vanden Heuvel, editor and publisher of The Nation magazine, which endorsed de Blasio early in the mayoral primary.

“Mayor de Blasio has become an important symbol of a national populist agenda,” said vanden Heuvel, who attended the Gracie Mansion gathering. “His mayoralty is being viewed by the country as a test case for progressive responses to what he considers the crisis of our time -- income inequality.”