The cumulonimbus that has settled over the John A. Wilson Building continues to expand.

This week, the city’s attorney general delivered startling allegations that D.C. Council member Harry Thomas Jr. (D-Ward 5) diverted city funds for his personal use. Add that to the sad litany of recent city hall scandals — the alleged payoff by Mayor Vincent C. Gray’s (D) campaign to Sulaimon Brown; Council Chairman Kwame R. Brown’s SUV dealings and unreported campaign contributions; the chief of staff to Jim Graham (D-Ward 1) who pleaded guilty to accepting illegal gratuities.

How does the city begin to mend the tears in its ethical fabric?

Chairman Brown (D) and Mary M. Cheh (D-Ward 3) think that legislation can help. The Comprehensive Ethics Reform Act that they co-introduced last month would overhaul the way the D.C. government polices itself.

It would establish a new Office of Government Accountability that would “investigate any matter involving lobbying, conflict of interest, financial disclosures, and other ethical matters and standards of conduct.”

An Ethics Advisory Committee would be tasked with keeping rules up to date. There would be new requirements for ethics training for city employees, and lobbying disclosure forms would be more stringent. Elected officials, for the first time, would have to disclose clients of their private businesses and their dealings with nonprofit entities. And there would be new restrictions placed on elected officials’ fundraising, which would be permitted only for a “nongovernmental bona fide charitable activity benefiting the District of Columbia.”

Sounds good. So why is Robert Wechsler skeptical?

He does research for City Ethics, a group that advises counties and municipalities. The D.C. Council hired it to review its ethics policy in 2009, after revelations that Marion Barry (D-Ward 8) had given city contracts to a girlfriend and directed city money into nonprofit groups that he had created and controlled.

“I saw what a mess it is,” Wechsler said of D.C.’s ethics laws, a miasma of confusing and overlapping rules with unclear lines of enforcement and accountability.

The Brown-Cheh bill “is a step in the right direction, no doubt about it,” he said. “But it’s a piecemeal solution when there could be a more truly comprehensive solution.”

For example: The Office of Government Accountability has broad powers to probe potential ethical lapses, but its enforcement powers are nil, so it must refer any wrongdoing to the “appropriate authority.” And its findings can be appealed not once, but twice — to the Board of Elections and Ethics and to the District courts. “It could take years before it even gets to an ‘appropriate authority,’ ” Wechsler said. “It’s not even clear who makes a decision of where it goes. It’s not very detailed compared to the average city ethics code. Many towns’ ethics codes are more detailed.”

Cheh readily admits that the bill might not be ideal, deploying the old adage about not letting the perfect be the enemy of the good.

“Is it something that’s the end-all and be-all? I don’t think so, but it’s a start,” she said Thursday. “Maybe it’s better to get something with advantages and good features and get the ball rolling.” The council certainly has an interest in moving swiftly to do something to restore the public’s confidence in it.

That tends to be the way ethics laws get written, Wechsler said — in crisis. “A scandal happens, so they do some rewriting. That’s the easy thing to do,” he said, “easier than sitting down and creating a really good integrated program. . . . They have all these laws, and they are trying to build on them. There’s not a very solid structure to build on, let’s put it that way.”

An increasingly favored ethics model is to establish an independent ethics commission — completely independent, Wechsler said, not appointed by the elected officials it would have to police. Instead, the commission might be filled with leaders of local institutions — bar associations, universities, the League of Women Voters, for example. But elected officials tend to resist relinquishing that kind of power.

Cheh rightly noted that election officials bent on peddling their influence or embezzling city funds are going to flout laws, no matter how comprehensive they might be.

“How can a law protect you against people who are determined to misbehave?” she asked. “It can’t protect you entirely, but it can help.”

The real challenge is creating a culture where ethics isn’t just a set of rules to navigate around. A culture where, for example, it’s not enough for an elected official to simply return a bribe, satisfied that he’s followed the letter of the law — as Graham did, it was revealed this week.

In a truly ethical D.C. government, more would have been done. “That’s the really hard part,” Wechsler said. “The laws can only do so much.”