For years, Portsmouth Concerned Citizens (PCC) has made transparency one of its rallying cries.

The taxpayer advocacy group regularly calls on town officials, boards and commissions to conduct business openly, disclose information promptly and explain decisions fully to the public. Transparency, PCC members often remind us, is essential to public trust.

Which is why the controversy surrounding an anonymous mailer in the Portsmouth Multi-Purpose Senior Center board election is so troubling.

The flyer, mailed to some residents ahead of Monday’s election, endorsed five candidates and urged members to vote for those who would promote “transparency,” “accountability” and protection of the senior center’s interests. It also focused heavily on the ongoing debate over a proposed affordable housing development adjacent to the center.

There is nothing inherently wrong with endorsing candidates. Individuals and organizations have every right to support candidates they believe will best serve an organization. Elections are contests of ideas, and advocacy is part of the democratic process.

The problem is that voters deserve to know who is doing the advocating.

The flyer carried no signature, no return address and no indication of who paid for it. To many recipients, its format and references to the senior center created the impression it may have originated from the organization itself — an impression senior center officials quickly and publicly rejected.

That should have been the moment for whoever was responsible to step forward.

Instead, silence followed.

The Portsmouth Times contacted all five candidates featured in the mailing using the email addresses provided on the flyer itself. Not one responded before election day. If the candidates had no involvement, they had an opportunity to say so. If they knew who was responsible, they had an opportunity to clarify matters. If they supported the mailing, they had an opportunity to defend it.

The public heard nothing.

Meanwhile, PCC leaders denied their organization sent or funded the mailer. Yet after those denials, this newspaper obtained an email from PCC President Larry Fitzmorris that distributed an identical copy of the flyer and stated that PCC had voted to endorse those same five candidates. Whether PCC actually created the mailer, financed it or merely circulated it remains unclear.

When presented with the email and given another opportunity to explain the apparent contradiction, Fitzmorris said the email was from PCC, “sent only to our membership, that has been leaked to you.” At the same time, he continued to deny that “PCC drafted, funded or mailed that mailer.”

That lack of candor is disappointing.

PCC is, of course, a private organization. It is under no legal obligation to publish a membership list or conduct its meetings in public. But groups that routinely demand openness from others should be prepared to meet a similar standard themselves, particularly when they seek to influence public affairs.

Credibility is built not merely by calling for transparency, but by practicing it.

The unanswered questions surrounding this mailer may never be resolved. Perhaps someone will eventually claim responsibility. Perhaps not. But the episode serves as a reminder that transparency is not a slogan to be deployed when convenient. It is a principle that applies equally to elected officials, advocacy groups, candidates and citizens.

If Portsmouth residents are expected to trust those who seek influence in the community, they deserve straightforward answers about who is speaking to them and why.

That should not be a controversial expectation.