Whatever form the final agreement to raise the federal debt ceiling takes, it will surely include some sort of promise that Congress and the president will pursue “tax reform” or a “tax overhaul.” It can’t be called a tax increase, but the purpose will be not just to close tax loopholes and keep basic marginal rates low, but also to bring revenues up from their current level of 14.4 percent of gross domestic product, a level last seen in the Truman administration.

The very words “tax reform” are music to the ears of good-government liberals like me—and Barack Obama. They bear the hope of bipartisan compromise and grand bargains in which everyone wins. Conservatives get lower rates, liberals get a fairer tax code with more revenues for social programs, and fewer giveaways to favored industries. For folks like us, Showdown at Gucci Gulch, the book about the 1986 tax reform, is like a national epic; the moment in the book when then-Senator Bob Packwood drinks a pitcher of beer over lunch and decides to throw out the messy bill his Finance Committee has produced and start over with a clean tax-reformer’s dream bill is like Aeneas’s arrival in Latium.

There are no Packwoods around today (while remembered now for his egregious sexual harassment, he was also a smart moderate Republican of a type long ago banished from the party), and nothing about tax reform is going to be any easier than the debt-limit deal itself. Still, if a budget deal commits Congress to do something, the goal of tax reform can be much more than just moving the long-term revenue line a little closer to the spending line. Because the tax code sets some of the basic parameters of our economic structure, it can also be an opportunity to move the whole country in the direction of greater fairness, growth, and financial stability.

IF AND WHEN the tax reform moment arrives, you’re guaranteed to hear two principles tossed around a lot. One is that we should have a “clean” tax code that doesn’t try to “pick winners” through narrow deductions and credits. The other is that we should “tax what we want less of, and not what we want more of.” That second principle conflicts with the first, since it implies picking winners. But one lesson from past tax reform: There’s no such thing as a purely clean code—taxes always create incentives that change the economic structure and create winners and losers, often in ways that aren’t obvious.

One thing that we want less of, or should want less of, is economic inequality. From the stagnation of wages and opportunity in the middle and low end of the income spectrum, to the staggering gains at the top (the 152,000 people in the top one-tenth of one percent receive more than ten percent of all income), the thirty-year “great divergence,” as the economist Claudia Goldin has called it, represents a profound social change with grave consequences for social cohesion, economic instability, and political polarization.