Marc-William Palen is a historian at the University of Exeter. His book, "The 'Conspiracy' of Free Trade: The Anglo-American Struggle over Empire and Economic Globalisation, 1846-1896" is now available in paperback.

The relief effort in Puerto Rico has been insufficient, in part thanks to decisions made more than a century ago. (Hector Retamal/AFP/Getty Images)

The tragedy befalling Puerto Rico after Hurricane Maria — beholden as it is to the dictates of Washington — stems directly from the territory’s subordinate political status. This was highlighted again last week when Carmen Yulín Cruz, mayor of the territory’s largest city, made a desperate appeal to President Trump “to save us from dying.” The mayor’s plea provoked only scorn from the president, who took time out from working on his golf stroke in New Jersey to lash out at her on Twitter for her “poor leadership.”

Trump’s callous response only underscores Puerto Rico’s precarious position within the U.S. body politic; nearly half of Americans today don’t even know that Puerto Ricans are U.S. citizens.  This combination of apathy and amnesia is symptomatic of more than a century of absent-minded imperialism, stretching back to when Puerto Rico became a U.S. colony.

Cruelty mixed with the veneer of compassion and stewardship is the essence of colonialism. Global Opinions editor Karen Attiah says President Trump reinforced that in Puerto Rico, where he suggested survivors of Hurricane Maria are a burden. (Adriana Usero,Kate Woodsome/The Washington Post)

The decision made in the late 19th century to make Puerto Rico a colony without the full political equality of statehood is now crippling the island’s ability to recover from Maria. The Trump administration’s initial enforcement of the Jones Act, which restricts foreign ships from entering Puerto Rican ports, and the indifference of many Americans toward the plight of Puerto Ricans were born out of this nearly forgotten turn-of-the-century imperial decision. Americans must reconcile and rectify their imperial legacy, or Puerto Rico will continue to suffer.

Puerto Rico was among a handful of colonies acquired by the United States in the wake of the Spanish-American War in 1898. Almost immediately, members of Congress began to debate what to do with America’s new possession, with little concern for what Puerto Ricans themselves wanted. The main question: Would the United States treat Puerto Rico as it would a state, or would it treat it like a foreign country?

One issue overrode all others in determining the result of that debate: free trade. For Republican protectionists back then, as with Donald Trump now, free trade was seen as a conspiracy of foreign interests to undermine U.S. industries. Paranoid, protectionist Republicans not only decided that Puerto Rico should be prohibited from trading freely with the rest of the world, they initially didn’t even want it to trade freely with the rest of the United States.

Why? Most immediately, because unhampered free market competition with Puerto Rico was a threat to powerful domestic sugar-growing interests.

But Republicans also feared that free trade with Puerto Rico might set an unwanted precedent for other newly acquired U.S. colonies such as the Philippines. As a spokesman for President William McKinley put it in 1900: “He don’t want any legislation for Puerto Rico that will keep us from legislating for Manila.” Puerto Rico thus became a case study that would shape how the United States would treat its colonies — and the fallout has shaped Puerto Rico’s quasi-colonial status since.

By 1900, the colonial free trade debate was so bitter that, for imperialists and anti-imperialists alike, the matter of Puerto Rican tariff policy had become “the most momentous that has come up since the Civil War.” And with Republican protectionists holding the reins of power, the outcome was hardly a surprise. With the help of a Republican-controlled Congress and a sympathetic Supreme Court, McKinley, the “Napoleon of Protection,” decided upon discrimination and coercion rather than free trade for Puerto Rico.

McKinley did so over the protestations of Puerto Ricans who desired autonomy and free trade.

He also faced opposition from anti-imperialists in the United States, who condemned the protectionist decision as “the entering wedge of ‘imperialism.’ ”

The tariff issue then made its way to the Supreme Court. In 1901, the court gave its legal stamp of approval to the protectionist American Empire in the first of the infamous Insular Cases that determined U.S. colonial trade policies for decades to come. The Constitution, the court concluded in Downes v. Bidwell, did not follow the flag, and thus Congress could control Puerto Rican trade policy and discriminate against Puerto Rican imports. Sydney Brooks, a contemporary British observer, shrewdly noted that the decision was made, not “for the benefit of Porto Rico . . . but to establish the principle, now ratified by the Supreme Court, that Imperialism did not imply free trade within the Empire.”

The Jones Act, which dictates that only ships built in the United States and owned by U.S. citizens are allowed to enter Puerto Rican ports, was passed two decades later, driven by similar thinking.

Early last week, the protectionist Trump administration initially denied a request to waive the Jones Act restrictions in the interests of promoting the U.S. shipping industry, even though doing so meant hindering cheap and speedy foreign importation of gasoline and other much-needed supplies to Puerto Rico. The move was a continuation, however unwitting, of more than a century of U.S. imperial policies.

Blowback from Trump’s protectionist move forced the administration to reverse course. But the U-turn might be too little too late, highlighting once again that, until Puerto Ricans are granted full political equality, they will continue to be held hostage to the whims of an absent-minded empire.