In a recent poll, 41 percent of respondents said they did not believe that Puerto Ricans were U.S. citizens, and 15 percent were not sure. Only 43 percent answered that Puerto Ricans were U.S. citizens. Today, being born in Puerto Rico is tantamount to being born in the United States. But it wasn’t always that way, and a lot of ambiguity still remains.

Contrary to what many people believe, the Jones Act, which Congress passed 100 years ago, was neither the first nor last citizenship statute for Puerto Ricans. Since 1898, Congress has debated 101 bills related to citizenship in Puerto Rico and enacted 11 overlapping citizenship laws. Over time, these bills have conferred three different types of citizenship to persons born in Puerto Rico.

I’m part of an ongoing collaborative project that seeks to document and clarify the laws around citizenship for Puerto Ricans. For the first time, we’re making available to the public all citizenship legislation that has been debated between 1898 and today in a web-based archive.

These archives show that U.S. law still describes Puerto Rico as an unincorporated territory that can be selectively treated as a foreign country in a constitutional sense. This contradiction is at the heart of a range of discriminatory laws and policies used to govern Puerto Rico and the more than 3.5 million U.S. citizens living on the island.

The state of Puerto Rico

Debates over the citizenship status of persons born in Puerto Rico are usually centered around the territorial status of Puerto Rico.

The United States annexed Puerto Rico during the Spanish-American War of 1898. Between 1898 and 1901, U.S. academics, lawmakers and other government officials began to invent a new tradition of territorial expansionism. It enabled them to strategically annex territories throughout the world like Guam, American Samoa, the U.S. Virgin Islands and the Mariana Islands, for military and economic purposes without binding Congress to grant them statehood. To support this effort, they also created interpretations of the Constitution that would allow them to govern Puerto Rico and the other territories annexed during the Spanish-American War.

As the Supreme Court first established in Downes v. Bidwell (1901), territories annexed after 1898, those mostly inhabited by nonwhite populations or so-called “alien races,” would be ruled as “unincorporated territories,” or territories that were not meant to become states.

In Downes, the court was asked to rule on the constitutionality of a tariff on goods trafficked between the island of Puerto Rico and the mainland imposed by the Foraker Act, a territorial law enacted to govern Puerto Rico in 1900. Opponents of the tariff argued it violated the Uniformity Clause of the Constitution, which barred tariffs on goods trafficked within the United States. A majority of the justices, however, concluded that Puerto Rico was not a part of the U.S. for the purposes of the Uniformity Clause and affirmed the tariff. In effect, the U.S. treated Puerto Rico as a foreign country.

A lingering question in this case was, how does the Constitution apply to unincorporated territories? Specifically, does the Citizenship Clause of the 14th Amendment apply?

Are Puerto Ricans constitutional citizens?

Supreme Court Justice Edward D. White attempted to answer this question when he wrote a concurring opinion in Downes v. Bidwell. His opinion is regarded by scholars as the source of the doctrine on territorial incorporation. The doctrine contains three basic elements.

First, it recognizes a difference between incorporated territories – those meant to become states – and unincorporated territories.

Second, Congress is granted absolute power to enact legislation extending or withholding constitutional provisions. In other words, only fundamental constitutional rights are guaranteed in unincorporated territories, not the full application of civil rights.

Third, unincorporated territories can be selectively governed as foreign locations in a constitutional sense. That means that so long as Congress is not violating the fundamental constitutional rights of Puerto Ricans, Congress can choose to treat Puerto Rico as a foreign country for legal purposes.

The prevailing consensus to this day is in line with White’s interpretation – that the Citizenship Clause of the 14th Amendment does not extend to Puerto Rico. Since the Downes ruling, for 116 years, Congress has governed Puerto Rico as a separate and unequal territory.

The Foraker Act at the heart of the Downes case had also imposed Puerto Rican citizenship on persons born in Puerto Rico. People who were born in Spain and residing in Puerto Rico were allowed to retain their Spanish citizenship, or acquire Puerto Rican citizenship or U.S. citizenship. Island-born were barred from retaining their Spanish citizenship, the citizenship that they acquired while Puerto Rico was a province of Spain, and from acquiring a U.S. citizenship.

But there was a big problem. At the time, persons seeking to naturalize and become U.S. citizens were required to first renounce their allegiance to a sovereign state. For Puerto Rican citizens, this meant renouncing their allegiance to the U.S. in order to acquire U.S. citizenship. This contradiction effectively barred Puerto Ricans from acquiring U.S. citizenship.

In 1906, Congress added a section in the Bureau of Immigration and Naturalization Act that waived the requirement to renounce an allegiance to a sovereign state. As my research shows, in 1906 Puerto Ricans began to naturalize in U.S. district courts throughout the mainland.

The Jones Act of 1917 included a collective citizenship provision. It enabled people living in Puerto Rico to choose between keeping their Puerto Rican or other citizenship, or acquiring a U.S. citizenship. Because the Jones Act did not change Puerto Rico’s territorial status, persons subsequently born on the island were considered U.S. citizens by way of “jus sanguinis” (blood right), a derivative form of U.S. citizenship. In other words, persons born in Puerto Rico were born outside of the United States but still considered U.S. citizens.

It wasn’t until 1940 that Congress enacted legislation conferring birthright, or “jus soli,” (right of soil) citizenship on persons born in Puerto Rico. Whereas persons born in Puerto Rico prior to 1940 could only acquire a naturalized citizenship if their parents were U.S. citizens, anyone born in Puerto Rico after 1940 acquired a U.S. citizenship as a direct result of being born on Puerto Rican soil. This legislation both amended and replaced the Jones Act. The Nationality Act of 1940 established that Puerto Rico was a part of the United States for citizenship purposes. Since Jan. 13, 1941, birth in Puerto Rico amounts to birth in the United States for citizenship purposes.

However, the prevailing consensus among scholars, lawmakers, and policymakers is that Puerto Ricans are not entitled to a constitutional citizenship status. While Puerto Ricans are officially U.S. citizens, the territory remains unincorporated. This contradiction has enabled the governance of Puerto Rico as a separate and unequal territory that belongs to, but is not a part of, the United States.

On June 11, Puerto Ricans will vote in a nonbinding status plebiscite deciding whether Puerto Rico should become a state or a sovereign country. If a majority votes for statehood, the question is whether Congress will grant 3.5 million U.S. citizens the ability to live in the 51st state.

Charles R. Venator-Santiago is associate professor of political science and El Instituto: Institute of Latina/o, Caribbean and Latin American Studies at the University of Connecticut.