NYC mayor 'optimistic' about Hillary Clinton but wants to hear more

New York City Mayor Bill de Blasio stopped short of endorsing Hillary Clinton for president but said he's "optimistic" about the direction of his former boss's campaign.

"I have seen some clear signals, some clear ideas come out of her conversations in Iowa," de Blasio said Wednesday on MSNBC's Morning Joe. "Certainly, the speech on criminal justice reform the other day I thought was very powerful. What she said yesterday about immigration. I think she is beginning to fashion a progressive agenda.  I think a lot of us understandably want to hear the core ideas around fighting income and equality because that's what people struggle with."

De Blasio, who ran Clinton's 2000 Senate campaign in New York, has been noticeably absent from the band of prominent Democrats supporting the former secretary of State. Like Sen. Elizabeth Warren of Massachusetts, another favorite of liberals, de Blasio has been cautious about fully embracing Clinton.

The mayor will unveil an agenda for progressives on Tuesday, from the steps of the U.S. Capitol. He's taking a page from the playbook of Newt Gingrich, whose conservative Contract with America was touted with great fanfare in the same way ahead of the historic 1994 elections that gave Republicans the majority.

"I think the world of Hillary. I worked with and for her for years," de Blasio said. "The bottom line here is that we are in a moment of history where we need to hear a clear vision for addressing the economic reality. A number of us have put together such a vision that's going to go right at the question of income and equality, which I think is the crisis of our times."