WASHINGTON -- A month after voters last year had given Democrats control that would elevate Nancy Pelosi as speaker of the House, she received a letter from a trial lawyer in Santa Ana, Calif., named Daniel J. Callahan. "We look forward," he wrote, "to the New Direction of America, and to your dedication to putting an end to the fleecing of the American taxpayers and death to its citizens in the name of war profiteers such as Blackwater." That plea was answered last week by House hearings.

Callahan did not disguise his political orientation, requesting a full-scale investigation of an "extremely Republican" company: Blackwater Security Consulting, which provides security guards in Iraq. He asked Pelosi to investigate "now that there has been a shift in power in Congress." It required nearly a year for Chairman Henry Waxman to find a peg for holding a House Oversight and Government Reform Committee hearing last Tuesday.

Callahan and Waxman are driven by quite different motives. The trial lawyer seeks a big payoff for the families of four Blackwater guards who were ambushed and massacred three and one-half years ago. For the congressman, a fierce Democratic partisan, this issue is part of his wide-ranging investigation of the Bush administration, with emphasis on its conduct of the Iraq war. Their divergent paths merged last Tuesday and will continue together for two more planned hearings.

On March 31, 2004, four Blackwater employees in Iraq were killed and their bodies desecrated at Fallujah by attackers wearing Iraqi police uniforms. Under federal regulations, their families would receive $57,000 each year and be prohibited from suing Blackwater. But Callahan and North Carolina lawyer David Kirby (erstwhile partner of former Sen. John Edwards) went to court at Raleigh, N.C., (Blackwater's home) claiming gross negligence.

The case immediately elicited interest from investigation-minded Democrats in Congress, Rep. Waxman and Sen. Byron Dorgan. But they could do little until the Democrats gained control of Congress. Waxman's inquiry still received scant attention until Sept. 16, when Blackwater private security forces were reported to have killed 11 Iraqis. The Iraqi Ministry of the Interior -- which has been discredited and dysfunctional -- assailed Blackwater's performance.

Four days later, Waxman demanded testimony from Blackwater founder and CEO Erik Prince, a former Navy Seal lieutenant with Republican connections. On that same Sept. 20, Callahan initiated a telephone conversation with Blackwater counsel Joseph E. Schmitz. A memo by lawyers representing Blackwater quoted Callahan as saying "the company can bury" its bad publicity "by paying $20 million . . . consisting of $5 million per family." (Callahan confirmed to this column that he mentioned $20 million but also required the families' approval, Blackwater's release of its after-action reports and a plaque honoring the dead men at the place they were killed.)

No deal was struck. While the trial lawyers wanted money, Democrats wanted more bad publicity for Blackwater -- and the Bush administration. Paradoxically, the killing of 11 Iraqis, which put Blackwater on front pages and evening TV news and made possible a show hearing, could not be mentioned Tuesday because of an ongoing criminal investigation. The core of the anti-Blackwater hearings was the Fallujah incident, as Callahan clearly hoped when he wrote Pelosi a year ago.

Questioning by Democrats seemingly came straight from Callahan's legal briefs. Democratic Rep. Jan Schakowsky called the Fallujah operation an "infamous mission fraught with mistakes of the Blackwater supervisors." Democrats ventured into broader questions of whether private firms should function in war zones, though they did not make clear who would guard State Department personnel and visiting members of Congress.

Waxman followed the path suggested by Callahan to Pelosi a year ago, which pointed to a crusade against "corporate greed." But the focus was on the plaintiffs in the pending lawsuit, with families of the Fallujah four present in the congressional hearing room. Asserting that their loved ones were "killed in a tragic and unnecessary accident," the chairman said to the survivors: "I know many of you believe that Blackwater has been unaccountable to anyone in our government. I want you to know that Blackwater will be accountable today."

What could have been a serious inquiry into the role of private firms performing tasks that cannot be handled by the U.S. and its overburdened military was inseparable from a precedent-setting private lawsuit. It was attached from the moment trial lawyers seeking a big payout solicited help from Democrats seeking a political advantage.