The campaign to provide more affordable transit fares to low-income New Yorkers is intensifying as Mayor de Blasio and the City Council stake out positions in advance of budget talks.

What began as an alliance between the Riders Alliance and the Community Service Society has become a political force, with deep support on the City Council and among major unions, as well as most borough presidents and district attorneys. Today the “Fair Fares” coalition showed its strength on the steps of City Hall, calling on de Blasio to fund half-price MetroCards for the 800,000 New Yorkers living below the federal poverty line.

De Blasio says he supports the $212 million program, but he’s declined to fund it. Speaking to reporters yesterday, the mayor said the city budget — which is projected to include $88.7 billion in spending in the next fiscal year, up from $70 billion in the last year of the Bloomberg administration — did not have room for Fair Fares. De Blasio has said it should instead be paid for by Albany, where his millionaire’s tax, which was supposedly going to pay for it, went nowhere.

Meanwhile, with the energetic support of Speaker Corey Johnson, who’ll be leading the City Council’s budget negotiations with City Hall, the Fair Fares coalition is gaining momentum.

In the two years since its launch, the coalition has grown to include the district attorneys of Manhattan, the Bronx, and Brooklyn; 44 City Council members; four borough presidents; and 68 advocacy organizations and unions.

Last year, under Melissa Mark-Viverito, the City Council proposed an initial $50 million down payment as a sort of trial run for Fair Fares. Johnson says he’ll push for the whole package.

“This is not about handing out money to the MTA, it’s giving a hand up to New York City’s poor,” Johnson said at today’s rally. “It’s about ensuring that if you live in New York City, you have the ability to ride mass transit and get around our city.”

“The council is fully committed to making this a major cornerstone and pillar of our [budget] negotiations,” he said. “The city should not wait on Albany to pass a millionaires tax.”

In 2016, NYPD arrested 26,000 New Yorkers for fare evasion, almost 92 percent of them people of color. Those numbers declined in 2017, in part due to Manhattan District Attorney Cy Vance’s decision to cease prosecuting most violators, but enforcement continues to fall disproportionately on the city’s most vulnerable communities.

Vance attended today’s rally along with Brooklyn DA Eric Gonzalez and Bronx DA Darcel Clark. He noted that the increase in transit crime predicted by the mayor and NYPD after the new policy went into effect has not occurred.

“Fare-beating is so often a crime of poverty,” Vance said. “[The justice system] should not be, or perceived to be, a collection agency for the MTA or any other government agencies, and relying on the criminal justice system is not an effective solution.”

Riders Alliance member Cynthia Kozikowski, a single mother of four who lives in the Bronx, said she struggles to afford transit fares for her children, and often has them climb under the turnstile.

“I sometimes have to borrow the money, sometimes I take it from the grocery or utilities,” she said. “I’m not asking for a free ride or a handout. If Mayor de Blasio says he is all about bridging the gap between the rich and the poor, then he should do what is in his power to fund fair fares.”