A worker vacuums a red carpet at the South Portico of the White House. (Jabin Botsford/The Washington Post)

PRESIDENT TRUMP has hired a cadre of lawyers to grapple with special counsel Robert S. Mueller III’s investigation into Russian election interference. Now, White House staffers are beginning to do the same. But who will pay the legal bills of those without the president’s deep pockets?

As the investigation apparently gathers steam, so does a debate over an Office of Government Ethics rule prohibiting anonymous donations to legal defense funds of government employees. While no such defense fund has yet been set up for the president's aides, its creation would help staffers shoulder the costs of the high-quality legal representation needed to weather questioning by Mr. Mueller's team. And the recent confusion over OGE rules shows that it's time for the office to make clear its position on requiring donor disclosures.

In 1993, the OGE released an opinion blessing anonymous contributions to legal defense funds. While the office swiftly backpedaled, the written guidance was never changed. So then-OGE Director Walter M. Shaub Jr. issued an advisory note to the opinion in May, warning that aspects of the guidance's reasoning "are not consistent with current OGE interpretation and practice." At some point since Mr. Shaub's departure from government in July, the notice changed to state that the 1993 guidance remains partially in force, though it also advises government officials to consult with the OGE before counseling employees.

According to Mr. Shaub, the revised note opens the door for the use of anonymous contributions. The OGE, on the other hand, says that the office's policy hasn't changed and that it is still counseling against such contributions. While there's no reason to doubt the OGE, it's also true that the text of the new advisory is vague and could be read permissively.

Legal defense funds for federal employees pose a difficult problem. Corruption is a concern: Staffers could become beholden to the outside interests subsidizing their legal bills. Yet if aides forfeit their ability to raise money to defend themselves when they enter government, then the risk of bankruptcy becomes a cost of public service. That seems overly harsh, especially when some — such as Mr. Trump — are better equipped than others to fund their legal representation.

The OGE’s 1993 opinion reasoned that anonymous contributions could solve this problem: How could someone be held captive to the interests of a donor whose identity remained a mystery? Yet as the office soon realized, it’s impossible to prevent donors seeking a favor from revealing themselves to their beneficiaries. The better solution is to allow legal defense funds but require a high degree of transparency so the public knows who is bankrolling counsel for government officials.

It's heartening that the OGE has signaled support for this approach — and that the White House will also work to disclose donors, according to an unnamed staffer who spoke with Politico. Yet with more and more of the president's aides retaining counsel, the OGE's written guidelines leave unnecessary ambiguity at a time when clarity is paramount. The office should take the opportunity to publicly affirm its long-standing ban on anonymous contributions and revise its advisory note to clearly reflect that commitment.