The hard part when Plan A goes awry is knowing when and how to settle for Plan B. Judging by this week’s showdown in Mililani over a proposed housing complex for seniors where arts-and-commercial centers had been planned, residents are clinging to the former and fighting the latter, tooth and nail.

Viewed from the outside, the uproar seems out of whack. Doesn’t Oahu need affordable housing for the elderly?

On closer inspection, the problem looks to stem from a lack of trust between the landowner, Castle & Cooke, and the residents who want delivery of what they saw in the master plan and sales presentations. What’s needed now is for public officials to mediate a use in which at least some of the community’s desires can be met, even if this single project can’t fulfill them.

A boisterous Mililani Mauka community turned out Tuesday for a late-night session before the neighborhood board, which failed to render a verdict on the current Meheula Vista housing plan.

The site — bounded on one side by a major thoroughfare, Meheula Parkway, and by the residential Kuaoa Street and Lehiwa Drive on the other — originally would have housed a commercial center occupying about 5 acres and a long-sought performing arts center on the roughly 3-acre parcel remaining.

The project by the nonprofit Oahu Arts Center now appears to be a nonstarter. Two years ago landlord Castle & Cooke ended its conditional agreement to donate the land, asserting that the nonprofit had not demonstrated the capacity to raise the development costs; the nonprofit disputes that finding.

Whoever is right on that score, nobody can be faulted for lamenting this outcome — least of all the taxpayers, who have already fronted real money in hopes that an arts center could be built. Grants of $100,000 and $200,000 from the city and state, respectively, have been spent on preliminary feasibility studies and financial plans. Reviving the project at some Central Oahu location should be a goal.

But the bottom line for this property is that although Castle & Cooke sacrificed some community trust by revising its plans, the developer has that discretion. It was a private agreement, and private agreements do sometimes run aground.

And at this stage, both sides need to get past the vitriol and move on to something more productive — such as negotiating an acceptable site plan. The housing developer who is poised to buy the property, Gary Furuta, already has shown willingness to work with the community and improve the project — restricting the number of cars allowed, for example.

Oahu has a critical need for homes that kupuna can afford. And although it’s not the use some hoped to see in this spot, surely it’s not a bad alternative.