For the first time, voters in Puerto Rico have advanced a non-binding referendum calling for statehood, a provision that could only be granted by the U.S. Congress.
Article IV of the U.S. Constitution gives Congress the authority to decide on state admissions. The last states admitted were Alaska and Hawaii in 1959.
U.S. President Barack Obama has said he would support the will of the Puerto Rican people on statehood. O'Brien says statehood is long overdue.
"Puerto Ricans have been citizens since 1917 but the quality of their citizenship has been one that has been dis-equal, or unequal rather," O'Brien added. "I think Puerto Ricans are clearly tired of that."