New York City Mayor Bill de Blasio took his campaign against income inequality to Iowa’s cornfields Thursday  and took a swipe at the president for not speaking out more for the poor.

He is also still refusing to endorse Hillary Clinton, who a top Buckeye State politician says loves her fellow Democrat nonetheless.

“I wish the president had early and often talked about income inequality and rallied the American people to address the issue,” the mayor said of Barack Obama at Drake University’s Harkin Public Policy Center in Des Moines, a day after speaking on the same subject in Nebraska.

“I wish that had happened earlier on in his administration.”

De Blasio, 53, who is rapidly becoming the national leader of the left, has made no secret that he wants to see his progressive policies front and center in the 2016 campaign.

RELATED: Mr. de Blasio goes to Iowa .

He spoke to about 60 people at the Harkin Institute for Public Policy and Citizen Engagement, reports Bloomberg Business.

The mayor demanded more taxes be slapped on America’s wealthy just as Republicans in Congress renewed efforts to repeal the Estate Tax  a move President Obama has said would mostly benefit the rich and make a middle class tax cut difficult.

“It’s clear that the wealthy among us could sustain higher taxes,” de Blasio said.

Bloomberg Business notesHe 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 was also asked about why he has not endorsed Clinton, who hired him to run her U.S. Senate campaign in 2000.

He said for the same reason he was in Iowa: the inequality issue.

"I have been beating this drum for quite a while with Team Clinton about the fact that these issues need to be addressed,” he said, according to NY1.

The man the Harkin Center is named for, longtime Iowa former Democratic Sen. Tom Harkin, is advising Clinton.

He said he had dinner with her Wednesday and when the snub came up, “she said ‘Oh, I love Bill de Blasio. Ran my campaign for the Senate. Great guy, great mayor.’”

Follow Metro Editor-at-large John A. Oswald on Twitter - @nyc_oz.