Kakaako Makai is, without a doubt, the most zealously guarded area within the entire redevelopment district, and for good reason. This is the last stretch of oceanfront property to be completely redeveloped.

Through energetic testimony pushing back against allowances sought for residential development on the ocean side of Ala Moana Boulevard, the community made it clear that the precious waterfront property should retain access, whether for low-rise commercial, educational, recreational or other public uses.

It’s hard to understand what about the proposed placement of a preschool in the zone doesn’t fit this land-use directive.

The Hawaii Community Development Authority, the state agency overseeing the special district’s planning and buildout, this week decided to suspend lease negotiations with Seagull Schools, which already has invested nearly half a million dollars in planning for a new preschool campus near the John A. Burns School of Medicine.

The private nonprofit operates six preschools on Oahu. Its website describes what would be its seventh, which it’s dubbed “The Kaka’ako First School project.”

The facility would encompass “a new 15,380- square-foot childcare center for up to 270 children on a three-quarter-acre parcel of land adjacent to Kakaako Park,” according to the site.

The three-building center would incorporate 11 classrooms, a commercial kitchen, administrative offices, two playground areas and a kupuna training and gathering room.

Seagull has been working with HCDA for three years, a good-faith effort that deserves an explanation from the authority.

It appears to be compatible with uses on adjacent parcels, including the Children’s Discovery Center.

Seagull officials pointed to $427,000 spent on an environmental assessment, a traffic study, soil sampling and building designs.

Of course, many prospective projects require this kind of up-front commitment as part of due-diligence work, and there’s never a guarantee. Seagull was necessarily taking a risk, but up-ending the advance work should be done only for a good reason. The ones supplied so far are not good enough.

An initial hurdle was a dispute over lease rent. Seagull had proposed a nominal $1 annual lease rent, and HCDA can’t be faulted for rejecting that offer.

The terms the agency proposed were for monthly rent starting at $1,000 monthly and rising to $6,000 over a 15-year lease period, with an option to go higher after that.

There was certainly the opportunity to come to terms rather than simply pull the plug on negotiations.

HCDA board member Steve Scott said the board decided it was premature to conclude a lease while HCDA’s master plan for the makai area is still in process.

But it’s hard to imagine why repurposing the site — which contains a deteriorating, unused maintenance building — would preclude the implementation of a master plan, which surely will take more than 15 years to realize.

And in the meantime, Kakaako would be putting its property to better use, bringing in revenue for the state. That would be preferable to simply letting an old structure sit empty.

The critique that the preschool is a private use of public land is unpersuasive. After all, the state has every notion of using some of its makai land for commercial purposes, so long as they’re low-density and accessible. The children’s museum, after all, is another private nonprofit.

Loretta Yajima, president of the Discovery Center, rightly observed that there could be synergy between the school and the center, becoming a “learning campus” enhanced by the park-like setting.

If there is a counterargument, the HCDA hasn’t made the case.