(Bloomberg View) Perhaps the only consensus in U.S. politics is that the Byzantine and loophole-riddled corporate tax code needs reform.

Hillary Clinton wants to curb the ability of companies to use overseas subsidiaries to shield profits from taxes, and such tax-avoidance strategies have been denounced by other candidates in the 2016 presidential election, including Donald Trump, Bernie Sanders and Jeb Bush, as well as by President Barack Obama.

They join a long line of would-be reformers who tried to put an end to such practices, largely without enduring success. This record of failure reflects the U.S.'s jury-rigged way of taxing overseas profits, which has become so complex that it is easily exploited by savvy corporations.

To understand why an arcane and inefficient system decried from all sides has resisted all efforts at improvement, it’s necessary to grasp the origins of the U.S. corporate tax, which was designed around the peculiar idea that corporations and shareholders are separate and distinct entities when it comes to taxation. This feature, arguably more than any other aspect of corporate taxation, accounts for the mess that reformers now confront.

The corporate income tax can trace its roots to the Civil War, when the Union imposed a levy on, among other things, the income that individuals realized from dividends and interest paid by corporations.

But unlike today, this arrangement treated the corporation and the individual shareholders as a unified entity. It did not tax the corporation on its profits and then impose another tax when it distributed those profits to shareholders. This reflected the idea that corporations were aggregations of individuals that had no existence independent of the shareholders.

The tax was repealed in 1871. But in 1894, Congress passed an overt tax on corporations that also effectively integrated shareholders and the corporation into a single taxable entity.

For example, the law imposed a 2 percent tax on the net income of corporations as well as on any undistributed corporate income. But shareholders who received dividends did not have to pay taxes on those profits. The tax historian Ajay Mehrotra has described this method as “essentially a crude form of withholding—a remittance method for taxing shareholder wealth.” Put differently, the corporation was merely a “pass-through entity” for its shareholders.

But as Mehrotra has observed, a very different idea of corporations had begun to emerge at the state level. Even as the federal law made shareholders liable for corporate taxes, a growing number of states began to tax corporations directly. Although there was considerable variation among states, the adoption of these laws reflected a new understanding of the corporation. A growing number of states began to treat them as people—artificial persons, to be sure, but ones whose earnings could be taxed. In this formulation, the corporation was an artificial entity given life by the state. It could therefore be regulated as well.

Some legal historians believe that this notion of the corporation as independent of the individuals who ran or owned it was derived from German legal thinkers such as Otto von Gierke and their English-speaking translators, most notably the German-born Ernst Freund, who later became a legal scholar at the University of Chicago. Freund, following von Gierke, argued that the corporation was greater than the sum of its parts—the shareholders. In his 1897 treatise, "The Legal Nature of the Corporation," Freund laid out the "real entity" theory of the corporate form. In this formulation, the corporation was its own thing: an entity that deserved separate consideration in the eyes of the law. (A mutation of this "real-entity theory" became a hot issue more recently when the Supreme Court ruled in the Citizens United campaign-finance case that companies had the same free-speech rights as people.)

Such ideas likely provided a way of understanding—and regulating—the corporate behemoths that began to dominate in the U.S. at the end of the 19th century. Unlike the family-owned businesses of the past, these gigantic enterprises divorced owners from day-to-day management, which gave corporations an autonomous status that had previously only been attributed to individuals.

While the notion of corporate personhood has often been used to protect corporations, here it became a means to control them via taxation. In 1909, when the federal Bureau of Corporations surveyed the ideological foundations of corporate taxation, it found that a consensus had emerged that "each person, natural or artificial, should contribute to governmental support according to his ability to pay.”

That same year, Congress passed the first law that enshrined this doctrine on the federal level: the Tariff Act of 1909. It imposed a “special excise tax with respect to the carrying on of doing business.” It was levied on corporations with net incomes of more than $5,000, and was described by President Howard Taft as “an excise tax upon the privilege of doing business as an artificial entity.”

In 1913, after the individual states ratified a constitutional amendment permitting an income tax, Congress passed the Revenue Act of 1913. It drew a formal distinction between corporate income taxes on the one hand and personal income taxes on the other. Nonetheless, the law still viewed corporations and shareholders as linked because corporate income could only be taxed once, either on the level of the corporation or the individual shareholder.

In succeeding years, however, the shareholders and the corporation drifted further apart in the eyes of the law. Then, in 1936, with the economy still mired in the Great Depression, President Franklin Roosevelt and his congressional allies sought to abolish the corporate income tax, replacing it with a punitive tax on undistributed corporate profits. As the legal scholar Steven Bank recounted, this provoked profound resistance from businesses.

In the end, a settlement was reached: The business community defeated the proposed tax in exchange for allowing “double taxation” —retaining the corporate income tax as well as a tax on dividends. This “ill-fated compromise,” as Bank described it, formally enshrined the idea that the same income could be taxed more than once. But it also formally divided the corporation from its shareholders when it came to taxation.

This idea that the corporation and shareholders can be treated as separate and distinct entities for purposes of taxation is at the root of the uproar in the campaign over so-called corporate inversions.

That's because it was fundamentally incompatible with another doctrine codified in the 1913 Revenue Act: the principle of worldwide taxation, which stipulated that American citizens and corporations would be taxed on their income, no matter where it was earned.

But as savvy tax lawyers quickly realized, the two doctrines offered a means of deferring the payment of taxes. That’s because a foreign corporation owned by American interests was considered a separate entity from the shareholders. At the same time, that same foreign corporation fell outside the purview of worldwide taxation. So long as the foreign corporation kept its profits offshore—deferring their repatriation home—taxes could be postponed.

This has led to innumerable deferral mechanisms that allow companies to park profits in overseas entities rather than bringing them home where they would be taxed. These include the much-publicized "inversions," which allow companies to nominally transfer their headquarters to low-tax countries by acquiring or merging with companies in those nations—paper marriages that change little in reality but enable profits to accumulate within a foreign corporate “person” that lives beyond the reach of worldwide taxation.

Such evasions have been the target of a series of would-be reformers, most recently among this year's presidential candidates. None has been successful.

The biggest problem may be that policy makers have taken a piecemeal approach instead of revisit the deeper history of corporate taxation and addressing the underlying contradiction at the heart of the U.S. system. Success would mean abandoning the cherished principle of worldwide taxation—an unpalatable option for many reformers.

Or they could focus on the conceit that corporations are artificial people who exist outside the flesh-and-blood shareholders who own them.

Regardless, if history is any guide, there is little reason to believe that the next president will be any more successful than his or her predecessors in peeling away the layers of a system developed over more than a century that has been protected from reform by its complexity and an industry of tax lawyers, accountants and lobbyists who thrive on gaming it.

This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners, nor of Accounting Today.