IN THE annals of modern American economic policymaking, among the most revered pieces of legislation is the Tax Reform Act of 1986. During the three decades since its passage, Democrats and Republicans alike have hailed the law not only for overhauling the country’s tax system, which Jimmy Carter famously called “a disgrace to the human race”, but also for doing so with bipartisan support in both houses of Congress. As Republicans embark on yet another sweeping rewrite of the tax code, many point to the 1986 effort as a model to emulate. It was “really something special”, Donald Trump said in August. However, admirers of America’s last comprehensive revision of its tax code should be disappointed with the GOP’s current attempts.

The bill that passed in 1986 took a long, arduous path to President Ronald Reagan’s desk. Originating out of a three-volume report by the Treasury department, it faced numerous brushes with death, and took more than two years to wind its way through Congress. The process included full committee hearings, markups and deliberations. The final bill eliminated many deductions, credits and exemptions that favoured some taxpayers over others. This generated new revenues, which were then used to reduce tax rates, mainly for low and middle-income individuals. The bill did not increase the budget deficit.

That legislative process bears little resemblance to the Republican Party’s current approach to tax reform. The authors of the last reform relied heavily on advice from professional economists. In contrast, Mr Trump’s Treasury department is yet to find a credible study supporting its claim that tax cuts will deliver enough economic growth to pay for themselves. It also removed from its website a paper arguing that the benefits of corporate tax cuts flow primarily to investors, rather than to workers. Centrist Democrats may have signed on to a bill lowering tax rates on companies and lower-income individuals. Nonetheless, instead of seeking bipartisan support, Republicans are using the restrictive procedure of budget reconciliation to try to push the legislation through on a party-line vote. And unlike the exhaustive review that occurred from 1984 to 1986, Mr Trump has promised to sign a bill by Christmas, just two months after the first legislative text was introduced.