The sight of a scandal-ridden celebrity or corporate executive invoking the Fifth Amendment is a hallmark of high-profile congressional hearings. Think of Enron Corp.’s Andrew Fastow, Hewlett-Packard Co.’s Ann Baskins or, after they crashed a state dinner, socialites Tareq and Michaele Salahi.

Now, congressional investigators may feel emboldened to do that more often.

In a new opinion, the District of Columbia Bar’s Legal Ethics Committee has made clear that it’s generally OK for lawyers in Congress to force a witness to appear, even when the lawyers have been told that the witness will refuse to answer questions under the Fifth Amendment’s right against self-incrimination.

Previously, congressional lawyers faced the threat of an ethics complaint for doing so. That’s because, in a 1977 opinion, the Legal Ethics Committee likened congressional lawyers to prosecutors, who are barred from calling such witnesses during a criminal trial because the move could unfairly sway a jury.

Lawyers who often represent witnesses before Congress see the new opinion as strengthening lawmakers’ authority.

“Defense lawyers have used the earlier opinion to attempt to persuade congressional investigators that it would be inappropriate of them to compel a witness publicly to take the Fifth,” said Robert Kelner, chairman of the election and political law group at Covington & Burling. “This was a tool that lawyers used to sway congressional staff,” Kelner said.

Bar Counsel Wallace “Gene” Shipp Jr., whose office handles ethics complaints against Washington lawyers, said he could not recall any public proceedings involving congressional lawyers caught up in this kind of situation. But the point, say lawyers with experience on and off Capitol Hill, is that the ethical question was often part of negotiations and it may not be anymore.

The dispute arises from dueling views about the value of high-profile congressional hearings. Defense lawyers say many clients have everything to lose by attending and that, at worst, a lawmaker such as the late Sen. Joseph McCarthy (R-Wis.) may call a witness only for the purpose of embarrassing the client. Many who have worked in Congress say hearings result in new information, sometimes ahead of the U.S. Justice Department or federal regulators, and they say witnesses shouldn’t be able to phone in their refusal to testify.

The Legal Ethics Committee revisited the issue at the request of Irvin Nathan, who until recently served as general counsel for the House of Representatives. Nathan, who is now the District of Columbia’s acting attorney general, declined to comment. The House GC’s office reviews committee subpoenas, and it’s responsible for protecting the House’s institutional interests.

Under the new opinion, published in January, a congressional lawyer would violate the Rules of Professional Conduct “only if there is no substantial purpose in calling a witness other than embarrassment, burden, or delay.” But anyone who would file an ethics complaint would find that to be a very high standard, lawyers say. “It’s impossible to prove that someone didn’t have a reason,” said Hogan Lovells partner Robert Bennett.

For example, Bennett said, a congressional lawyer could say that he did not know for certain that a witness would not answer questions until the witness actually appeared. In 2002, Gary Winnick, founder and chairman of the telecommunications company Global Crossing Ltd., was widely expected to invoke the Fifth Amendment when a House investigative subcommittee subpoenaed him to appear. But on the day of the hearing, Winnick appeared and answered the subcommittee’s questions.

Michael Stern, a former senior counsel in the House’s Office of General Counsel, said the D.C. Bar’s Legal Ethics Committee was always on shaky authority. Many lawyers on Capitol Hill are not members of the D.C. Bar, and even for those who are, Stern said, Congress has never agreed that its staff lawyers are subject to any state’s bar regulations. The House asserts that all legislative work is protected by the U.S. Constitution’s speech or debate clause, and staff cannot be questioned elsewhere.

“Our position was the D.C. Bar can’t prohibit a committee from calling whoever it wants and bringing them up, and if the witness decides not to appear, they can be held in contempt,” Stern said. He also wrote about the new ethics opinion on his blog, Point of Order.

A spokeswoman for the House Committee on Energy and Commerce, one of the most active investigative committees in Congress, referred questions about the issue to House General Counsel Kerry Kircher, who did not return messages. Several other committee spokespeople and lawyers either declined to comment or did not respond.

Sidley Austin senior counsel Thomas Green, a veteran of congressional investigations work, said he doesn’t see the new ethics opinion helping potential witnesses, but said chairs on Capitol Hill approach the issue differently.

“In connection with any given investigation, it is possible to convince the staff that it just simply would be inappropriate to call the witness merely to have a media moment where the witness takes the Fifth Amendment,” Green said. “At the same time, there are other members of Congress, committee chairmen, who are determined to experience the amusement of seeing someone take the Fifth.”

David Ingram can be reached at dingram@alm.com.