EMAILS AND LETTERS

He set to work with trade-association allies to sell the cuts to the wider business community. Their pitch: Repealing estate taxes would be a boon to family-owned firms, and the income-tax cuts would lift small-business owners, whose profits are taxed via their personal returns.

They also dangled a carrot: If business helped get this bill passed, Bush could press for a second directly addressing their desires.

Within months, a thousand business associations joined a new "Tax Relief Coalition." They inundated Congress with emails and letters. Congress passed the cuts largely intact, slightly reduced to $1.35 trillion.

By 2003 Blalock had a new job: senior vice president for what was then Fierce & Isakowitz. He brought with him an important new client. The Business Roundtable had become a key supporter of the first tax cut. It now wanted Blalock's help passing a second round proposed by Bush, a cut in taxes on capital gains and dividends. Congress passed a $350 billion bill.

By the end of the year, Blalock made partner and the firm added his name to the door. He moved from a $700,000 small brick Georgian home in a middle-class neighborhood to a $1.7 million house with a pool in one of the nicest sections of Alexandria, Virginia. His rise was no exception: Other aides who worked on the tax cuts went on to similarly successful lobbying careers.

The changes took hold shortly before the United States headed into its worst recession in 70 years. By 2009 the federal deficit surpassed a trillion dollars a year. Republicans and Democrats began fighting over whether to extend the tax cuts when they expire this year - and what role, if any, they played in rising income inequality.

Last year, two nonpartisan government bodies, the Congressional Budget Office and the Congressional Research Service, each undertook studies of income inequality for lawmakers. Both concluded that a major driver in the years leading up to the recession was the growth in capital gains among top earners - but that the cuts also reduced the equalizing influence of the income-tax system. The 2011 CRS paper said tax cuts were the second-largest contributor to the rise in inequality in the decade through 2006. (See accompanying article, "The economics paper that rattled Washington.")

Conservative economists point out that even after the tax cuts, the rich overall wound up paying a larger dollar amount in income taxes. That's mainly because the incomes of the wealthy kept climbing. The top quintile paid 15 percent more in taxes but made 30 percent more money in 2006 than in 1996, the CRS reported.

LEGISLATING EQUALITY

There is no serious disagreement that the rich saved far more on taxes than any other group relative to their incomes, however.

The Tax Policy Center, a think tank staffed by a mix of economists from both parties, calculated that two-thirds of the tax savings would go to the top quintile of households and 1 percent to the lowest quintiles in 2012. In dollar savings, that's $371,000 for the top 0.1 percent of households in 2012, $958 for the middle and $66 for the poor.