His target is Irvin Nathan, a lawyer being paid up to $250,000 by the House Judiciary Committee to investigate the Justice Department's purge of the federal prosecutors.

Under a Cannon amendment added to a lobbying reform bill, any private lawyer working for a congressional committee would be prohibited from lobbying Congress for one year, as would any member of that lawyer's firm.

In essence, firms would have to choose if they want to lobby or if they want to allow lawyers to work on the Hill.

"They have a choice. If they want to be here inside the tent like a staffer they ought to have the same limitations a staffer has," Cannon said.

Nathan, who is being paid up to $25,000 a month for up to 10 months for his work on the investigation, is not a registered lobbyist. But his firm, Arnold & Porter, has numerous clients, including United Parcel Service, numerous pharmaceutical interests, State Farm Insurance and the commissioner of Major League Baseball.

Nathan did not return calls seeking comment.

To top it off, if Cannon's amendment becomes law, its effective date would be today - the same day that the committee is scheduled to hear testimony from Monica Good- ling.

Goodling was the Justice Department's liaison to the White House and an aide to Kyle Sampson, a Utah native and former chief of staff to Attorney General Alberto Gonzales. She will be testifying under an immunity agreement worked out in part by Nathan.

Raymond Shepherd III, a Washington lawyer and former staff director for the Senate Permanent Subcommittee on Investigations, said it is understandable why Democrats turned to private lawyers to do investigative work, since they took control of the committees in January and it takes time to get a staff hired.

And there is merit to restrictions in those cases, he says. For example, a lawyer working for a committee should certainly not lobby that committee or Congress, and perhaps others at the firm should also not lobby that committee. But the Cannon amendment casts the net wider.

"To have that blanket prohibition seems awfully broad," Shepherd said. "If one were to take out any lawyers involved in a firm that do any lobbying that would preclude most, if not all, of the serious former congressional investigators from doing that kind of work."

That would include Shepherd, whose firm, Venable, does lobbying.

Democrats on the Judiciary Committee did not object to Cannon adding his amendment to the lobbying bill. A spokeswoman for Chairman John Conyers, D-Mich., declined to comment.

The full House is expected to consider the lobbyist restrictions on the floor, possibly as early as today. Cannon said he will be watching closely to make sure Democrats don't try to strip his language out of the bill and will fight any efforts to do it.

gehrke@sltrib.com