One mayoral candidate wants to ban testing. Another has pledged to close charter schools. And one wants to raise city income taxes to fund early childhood education.

Despite coming from different candidates, the pledges have one thing in common: They can’t be fulfilled from inside City Hall, despite mayoral control of the city’s schools.

The legislature and the governor’s office change tax laws and controls how school aid is spent. The Board of Regents and the State Education Department set policy and regulations around testing. And state’s charter authorizing bodies control which charter schools stay open and which close.

While the chief executive of New York City will always have clout in Albany and legislators might be inclined to go along with a newly elected mayor’s proposals, some of the candidates’ proposals would be hard sells. A review of candidates’ education proposals shows that they have been less than eager to talk about these limitations on the campaign trail, leaving questions about their ability to follow through on key elements of their education platforms.

“I think it would be more informative if various candidates would make it clearer when they say they’re going to do something to explain how they’re going to do it,” said Joseph Viteritti, a public policy professor at Hunter College.

Bill de Blasio’s prekindergarten tax

De Blasio’s tax plan would first have to get past his old boss, Gov. Andrew Cuomo, at a politically sensitive time for Cuomo.

It’s one of several hurdles that stand in the way of de Blasio’s proposal to raise the city’s income tax rate from 3.9 percent to 4.1 percent for families making over $500,000. The funding would go toward expanding prekindergarten and after-school services in an initiative that has been at the center of de Blasio’s progressive platform.

State law prohibits New York City from raising its local income tax rate without legislative action. De Blasio, who worked for Cuomo in the Clinton administration, says that as long as he can get the City Council to go along with the plan, Albany should follow.

“Albany, almost without exception, has agreed when a local executive and a local legislature calls for the right to self tax,” de Blasio said last month while discussing his plan. He cited as an example a two-year tax hike that Bloomberg sought and won in 2003, which raised rates for some residents who earned six-digit incomes.

But de Blasio could have a trickier time in Albany, whose elected officials, including Cuomo, face reelection in 2014.

Christine Quinn’s war on field testing

Quinn said she’d eliminate field testing during a major education speech back in January and has repeated the pledge throughout her campaign.

“Students do not have time to learn all the skills they need to succeed in college and beyond,” reads a January press release explaining Quinn’s rationale for banning the tests, which are administered to a sample of students as a way for test-makers to try out questions they might use in the future.

But the tests are administered by the State Education Department, and Commissioner John King has said field tests are an important strategy for ensuring that students take high-quality tests each year.

Update: Quinn ushered a resolution calling for their ban in May, specifically calling on the state to act.

In her campaign, she’s also acknowledged that she would need to work with King and the Regents if she is to follow through on her pledge. A press release from Quinn’s campaign last week said, ”As mayor, Chris will continue her fight to push the State Department of Education and Pearson to eliminate these stand-alone field tests.”

Charter school oversight 

Bill Thompson didn’t say much about charter schools when he gave a big speech about education, except to discuss the policy that he would have the least control over as mayor.

“Hold charters to the same standards as public schools,” read his campaign’s talking points. “Schools should be centers for learning and innovation. And if any school – public or charter – isn’t meeting that standard, Thompson will take action.”

But the Department of Education doesn’t control whether city charter schools open or close. It did give about a third of the city’s charter sector permission to open, but changes to the state’s charter school law in 2010 stripped the city of that right. It can still make recommendations to the state’s charter authorizers about closing schools, but lately it hasn’t been getting its way.

As mayor, Thompson would have some recourse against some low-performing charter schools. He could kick out charter schools occupying city-owned buildings for free, a significant punishment in a pricey real estate market.

Hidary’s expansion of portfolio schools

Quinn has also called for expanding schools that allow students to complete portfolio reviews to graduate, rather than pass most Regents exams. But Jack Hidary, an independent, says he’d want to triple the current number of 26 city “portfolio schools” to at least more than 100.

The Board of Regents is responsible for granting waivers to the small number of high schools that do not require Regents exams — there are 28 statewide — and it has been reluctant to add to that number. Instead the state is investing more in its Regents exams, seeking to make them harder to pass as a way to measure if students are ready for college.

Mayoral control

All of the candidates say they still want to have control over the school system — with changes. Bill Thompson said he’d give up a seat on the Panel for Educational Policy, in the spirit of collaboration, while Comptroller John Liu has said he’d overhaul the way panel members are selected.

Both proposals require Albany legislation. The currently governance structure, first passed in 2002 and renewed in 2009, expires in 2015. That deadlines give the candidates an easier way to lobby for the changes they want if lawmakers choose to extend mayoral control. The teachers union doesn’t want to wait that long. It’s pushing for legislation to give communities control of where to locate schools and strip a majority of votes on the PEP from the mayor.