SAN JUAN, Puerto Rico (AP) — Puerto Ricans have supported U.S. statehood in a vote that jubilant members of the pro-statehood party say is the strongest sign yet that the Caribbean island territory is on the road to losing its second-class status.

But Tuesday’s vote comes with an asterisk and an imposing political reality: The island remains bitterly divided over its relationship to the United States and many question the validity of this week’s referendum.

Nearly a half million voters chose to leave a portion of the ballot blank.