AMONG other things, the start of Donald Trump’s presidency this week heralds a collision between campaigning rhetoric and legislative and economic reality. What follows will be a learning experience for all, it is fair to say. Though not perhaps the most consequential of the looming reality checks, the outcome of a brewing debate over a proposed border-adjusted tax plan could prove a taste of things to come. As Mr Trump and his Congress work to make policy, there are many ways for things to go awry.

Both Mr Trump and congressional Republicans are keen to cut taxes on corporations. America’s inefficient corporate-tax system has remarkably high rates but leaks like a sieve, yielding a pitiful tax take (see chart). As a solution, Mr Trump favours a large cut in the corporate-tax rate, from 35% to 15%, and a chance for companies to repatriate foreign profits at a tax rate of 10%. Paul Ryan, Speaker of the House of Representatives and chief Republican policy wonk, has something very different in mind.

At present American firms are assessed for tax on their global income. This encourages multinationals either to use clever…Continue reading