The New York Times’s Joe Nocera writes about Wall Street. A longtime business columnist who now writes op-eds, Nocera does particularly sharp work when camped out at the intersection of government and finance. Want to know what’s up with Elizabeth Warren? Try this Nocera piece. Want to understand why capital requirements for banks should be stiff? Try this Nocera piece.

Knowledgeable, witty, edgy — Nocera’s just the kind of fellow I’d want to stand behind a podium if I were organizing a conference on banking.

The organizers of the ABS East ’11 conference apparently share my perspective. They signed Nocera up as one of the keynote speakers for the conference, which took place in mid-October in Miami. The annual conference is for “structured finance and securitization professionals”; ABS stands for “asset-backed securities,” or the very demons that caused our financial meltdown.

Sponsors of the conference include, well, basically all of Wall Street. Firms like Citi, Morgan Stanley, J.P. Morgan, Goldman Sachs, Bank of America, Merrill Lynch, Standard & Poor’s and many more are listed under the event’s lead sponsors.

The New York Times has a set of guidelines that appear to bar a guy like Nocera from doing a speaking appearance before such a confab.

Where permitted by local policy, staff members who deliver speeches may accept fees, honorariums, expense reimbursement and free transportation, but only from educational or other nonprofit groups for which lobbying and political activity are not a major focus. A staff member must consult with newsroom management before accepting a substantial speaking fee.

These very guidelines caused an inconvenience a couple of years ago for New York Times columnist Thomas Friedman, who was forced to return a $75,000 speaking fee that he’d received from the Bay Area Air Quality Management District.

Whether the organizer of a conference qualifies under New York Times policy as an educational or nonprofit group is unclear. What is clear is that Nocera has no regrets: “I certainly don’t view this as out of line,” he says.

That’s all Nocera would say about the matter; he declined to address the speaking fee or any discussions within the New York Times about his appearance. Also quiet on the matter were ABS East’s organizer and the American Program Bureau, a speakers’ agency that has a page for Nocera on its Web site; neither responded to requests for comment.

When asked about the gig, New York Times spokesperson Eileen Murphy replied:

There is some flexibility to our guidelines around speaking engagements, to be determined by either the standards editor (in the case of newsroom employees) or the editorial page editor or deputy editorial page editor (in the case of op-Ed). In this instance, a decision was made that Joe’s speech to this particular group was appropriate.

That could be good news for Paul Krugman, another highly talented and sought-after authority on politics and economics. The op-ed columnist once wrote this:

Before I went to work for the NY Times I did a lot of paid speaking, mainly to investment bank conferences outside the US… My fee for overseas talks was usually $40-50K.

I do very little paid speaking now, and no consulting, because the New York Times has quite strict rules: basically I can only get paid for speaking to nonprofits that have no possible interest in influencing the content of the column. It’s a good rule — read Eric Alterman’s book “Sound and Fury” to see how speaking fees can corrupt pundits — though it meant that I took a substantial income cut to work for the Times.

If Nocera is testing some boundaries at the New York Times, then it’s familiar territory for the columnist. A guy who has claimed his share of attention from the paper’s public editor, Nocera over the summer slammed Tea Party Republicans as “terrorists.” He later apologized. And a year ago, he landed in conflict-of-interest hot water with a column about Hewlett-Packard, Oracle and SAP. The editor’s note that ended up attached to the column tells the story best:

In the Talking Business column in Business Day on Saturday, Joe Nocera wrote about a lawsuit by Oracle against a division of SAP, claiming theft of intellectual property. Mr. Nocera learned after the column was published that Oracle was represented by the law firm of Boies, Schiller & Flexner, where his fiancée works as director of communications. To avoid the appearance of a conflict of interest, Mr. Nocera would not have written about the case if he had known of the law firm’s involvement.

In the spaces between hiccups, Nocera writes some of the most blistering and compelling business journalism anywhere. Far from an apologist for Wall Street, Nocera has written that the financial meltdown stemmed from regulatory failures; deplored Republican treatment of Warren, a proponent of banking regulations; and otherwise called for greater accountability for bankers.

So perhaps the New York Times decided that Nocera’s liberal, pro-regulation views were just so strong as to make him uncorruptible. A follow-up question is pending with the New York Times.