Democratic mayoral candidate Bill de Blasio strolled into the lion's den last week and spelled out his vision to what should have been a hostile crowd -- 750 members of the Association for a Better New York, an important local business group.

He didn't sugarcoat his pitch. He touted his divisive "tale of two cities" scenario, which casts New York as a place where the 1-percenters prosper with government help while the poor are stuck in poverty-wage jobs.

Yet the room gave him a respectful reception -- maybe because of his lead in the polls, maybe because of his easy wit, or maybe because he made a few decent points.

De Blasio was at his best when he talked about the need for New York to invest in upward mobility for its citizens.

He wants CUNY to become a stronger player in the city's bid to become a global leader in technical research. He thinks better health care for everyone is crucial. He's concerned about the shortage of affordable housing.

But unfortunately, he kept returning to the false notion that Wall Streeters and others danced through the Great Recession on the government's dime while the poor were left to go it alone. The centerpiece of his campaign is a plan to pay for citywide prekindergarten by hiking the city income tax on residents making $500,000 a year and up.

It's hard to imagine a dumber move. The top 1 percent of city earners accounts for 43 percent of local income tax revenue. If the city vilifies them -- while taxing them more -- why wouldn't they just choose to live elsewhere?

Contrary to de Blasio's message, nobody's getting a free ride, and to suggest they are is unfair. Residents of New York State pay the highest tax rates in the nation, says the Tax Foundation. Few other American cities go the extra mile and hit their residents with a local income tax.

New Yorkers have always had a strong belief in upward mobility, and de Blasio is compelling when he talks about measures for economic advancement and better health care that don't single out scapegoats. Playing one group off against the other is never a great way to get elected. The winner is left with a lot of damage to undo.