Say what you want about Mayor John DeStefano Jr., but the man knows how to make his school system look good. Following the teachers’ union’s overwhelming approval of their new contract, you’d think the mayor himself had found the balloon boy. Kind words flooded the national media, from The Wall Street Journal to Education Week, bringing endorsements from Education Secretary Arne Duncan and American Federation of Teachers President Randi Weingarten.

Were these congratulations in order? Not just yet.

Duncan and Weingarten, normally adversaries in the battle to reshape America’s schools, came together in support of the New Haven union plan. “I rarely say that something is a model or a template for something else,” Weingarten said, “but this is both.” “This shows a willingness to go into areas that used to be seen as untouchable,” Duncan cheered.

Why all the optimism? For the first time, the mayor was successful in getting the local union to agree to link teacher evaluations with student performance. The contract also allows for the lowest-performing schools in the district to be closed and reopened as charter schools. And finally, individual schools can adopt new work rules, including the extended school hours that have been a key component of success at charter schools, like Amistad Academy. Given the bitter struggles between mayors and unions in cities such as New York and Washington, D.C., DeStefano has reason to be proud.

But don’t jump up and down just yet. Many details remain to be settled, and existing caveats may water down that champagne you’re spraying. First, the effect of new teacher evaluations is unclear. Will they affect decisions on teacher tenure? How much power will principals have to fire teachers whose evaluations are not up to par, including those who already have tenure (which New Haven teachers acquire after only a few years)?

Second, the city’s ability to close low-performing schools is a good first step, but rebranding them as charter schools is disingenuous, since all teachers at reconstituted schools must still be unionized. But perhaps more importantly, what will be the criteria for closing a school, and who will get final say? With this mayor calling the shots, it’s hard to see how unbiased appraisals of student achievement will trump city machine politics. And many of these remaining issues — such as the teacher evaluation questions and criteria for closing schools — will be addressed by ad hoc committees comprised of mostly of teachers and city officials, largely out of the public eye.

The most encouraging aspect of the new contract is the provision for individual schools to change their work rules, and even that is suspect. Any changes must be agreed upon by three-quarters of teachers at any given school. If you’ve ever been to a school all-staff meeting, you know how hard it is to get three-quarters of teachers to agree on uniform chalk colors, much less voluntarily extending their work day.

Despite these limitations, the mayor is optimistic that his contract will win New Haven a portion of the $4.35 billion in federal “Race to the Top” funding. After the city and the union reached a tentative agreement, DeStefano said simply, “I expect to be rewarded” by the Obama administration. I would hope the mayor knows that “Race to the Top” funds are allocated to states, not districts.

And though New Haven’s contract will help Connecticut make its case for state-wide reform, the state has a ways to go to compete with the others. In particular, two criteria Connecticut is struggling to meet are a systemic plan for state reform and the creation of data systems to support instruction. Even if one assumes that New Haven is up to snuff, the state includes many other districts that can’t say the same, and Governor Jodi Rell hasn’t shown the eagerness for reform that Duncan seeks. DeStefano should think twice about promising more federal funding when so much of it lies outside his control.

What does lie within his control is competent leadership in executing school reform. The recent behavior of the superintendent does not bode well; two weeks ago, Reggie Mayo angrily stormed out of a meeting with a parents group when someone challenged Mayo’s unkept promise to provide Spanish translation at parent-teacher conferences. With DeStefano and Mayo’s mostly dismal record in charge of New Haven schools, a new union contract alone — however innovative it may or may not be — cannot ensure a promising future for the city’s children.

Sam Brill is a senior in Trumbull College.