It would be understandable if fans of public television's evocative documentary of the Civil War stayed tuned past 10:30 tonight in hopes that maybe, just maybe, the grand story would just keep going. Those who do will catch a flick on a very different national nightmare: the federal tax system.

It's "The Committee: Taxation With Representation," a historical documentary of the House Ways and Means Committee, writer of the nation's tax laws, author of taxes and tariffs that helped bring you the Civil War (the real thing, not the movie), the world wars, Social Security, the New Deal, Desert Shield and a lot of things in between.

Not to mention, er, the deficit, and the yet-to-come tax package to attack it. The film opens with a scene from the 1988 presidential campaign trail in which former Ways and Means member and then-candidate George Bush makes the political promise that now appears to be bringing the government to its knees: "Read my lips! No new taxes!"

Granted, this is not the stuff of box office sellouts, even if you add a little hype. As in: "The Deficit: The Movie!" Or: "You've read his lips. Now see the movie."

But the documentary, produced by prizewinning filmmaker Steve York and to be aired by WETA (Channel 26) tonight, makes clear what has become evident in the current deficit negotiations: The Ways and Means panel, little known outside inner-circle Washington and the corporate executives who try to influence it, has throughout history been a pivotal player in national dramas and crises. As an example: If and when a deficit-cracking deal is reached, the tax-writing committee will originate all of the tax laws and at least half of the spending bills to effect it.

"With the October 1 fiscal year deadline for the deficit negotiations coming up," said Jan Du Plain, WETA director of Washington communications, "we thought this was a very important film with very strong interest in the area."

But also interesting is the story behind the story, a Washington tale of how hundreds of thousands of dollars came to be invested in telling the history of a congressional committee that -- let's face it -- for all its power lacks the dramatic appeal of a film classic.

At the start and end of the film, the names of 40 companies, foundations and unions appear on the screen and a voice solemnly announces that they have underwritten the film because they "believe that an informed public is the key to effective, representative government."

Anyone who has prowled the halls outside the Ways and Means Committee during deliberations over major tax bills also knows that these same institutions include some of the leading beneficiaries of recent tax legislation, such as the Tax Reform Act of 1986 that raised the overall tax burden on corporations (but not all corporations) and cut individual tax rates.

Companies that were paying high taxes under the old act -- General Motors, IBM, Hewlett Packard Co., Kraft, RJR Nabisco, to name a few of the corporate logos that roll across the screen -- received tax cuts under the 1986 law, and "there was a lot of fondness among those people for Danny {Rep. Dan} Rostenkowski {(D-Ill.), the Ways and Means chairman}, a feeling that the process worked between business and the committee, and they wanted to express that," said an official of one of the concerns that donated money.

"Of course, most of the donors are corporations heavily affected by tax legislation, and so I'm sure some of them acted not just out of fondness but because they thought twice before saying no to something the committee wanted," the official continued. "It was your basic Washington basket of motivations."

The standard contribution, according to several of those involved, was $25,000. The money was donated not to Ways and Means, but to the U.S. Capitol Historical Society, which sponsored the movie, an in-depth book and a banquet attended by the donors, and past and present committee members (including Bush). The historic importance of the occasion was the 200th anniversary of the committee, one of the oldest in Congress.

Cornelius W. Heine, executive director of the historical society, said the group plans more documentaries about other committees, but he said he is doubtful that others, which lack the influence of Ways and Means, would inspire an outpouring adequate to finance a movie and other events.

The total raised, he said, was $800,000. Since the historical society is nonprofit and charitable, the contributions were tax-deductible, he said.

The airing of the movie also reflects the current dilemma in another way. WETA scheduled the film to appear the week of the opening of the new fiscal year -- more than a year after the committee's 200th birthday. Like the elusive deficit summit agreement, it slipped its deadline.