Puerto Rican supporters of presidential candidates Hillary Clinton and Barack Obama split distinctly on an issue not dealt with by mainland voters in the Puerto Rican primary Sunday, June 1st - Statehood for Puerto Rico. Senator Clinton's supporters in Puerto Rico heavily backed Statehood for Puerto Rico while Obama's did not, according to CNN's exclusive exit polls. Clinton handily defeated Obama by a margin of more than 2:1 with 68 percent to Obama's 32 percent in the island's party primary, the first since 1980. Among Clinton supporters, 72 percent said they want to see full U.S. Statehood for Puerto Rico, compared to 34 percent of Obama supporters.

Neither candidate took a direct position on the issue in the run-up to the primary, though Puerto Rico's former governor Democrat Carlos Romero Barcelo, a Statehood for Puerto Rico advocate was active in support of Clinton along with fellow Statehooder and Democratic Party National Committee member Puerto Rico Senator Ken McClintock. Statehood Democrat and candidate for Puerto Rico's non-voting Resident Commissioner in Washington, Pedro Pierluisi co-chaired the Obama campaign on the island. Roberto Prats who favors the status quo for Puerto Rico co-chaired the Clinton campaign.

For Clinton, Puerto Rico was a clean sweep in every demographic group, including those usually won by Obama on the mainland. The New York Senator dedicated considerable time and resources to Puerto Rico Democratic voters spending six days campaigning on the island, while Obama only made one visit to the territory. For Puerto Rican voters, these previously rare personal visits to the island clearly had a big impact on how they voted.

Other factors that may have contributed to Clinton's win are the vast number of Puerto Rican voters with strong ties to New York, and her husband former President Bill Clinton's popularity among Democratic voters in Puerto Rico.

The Democratic and Republican parties run the primaries and caucuses, and allow U.S. territories, such as Puerto Rico, to take part in the process; but voter turnout was expected to be higher. Some observers believe the inability to vote in the presidential and general election due to the island's unrepresentative status causes a lack of interest and disaffection; including a belief that the primary is meaningless for Puerto Rico voters. Only registered voters in the the fully incorporated 50 states already in the union and the District of Columbia currently vote in the general election.

Although neither Senator Clinton nor Senator Obama directly said they favored Statehood for Puerto Rico, in her victory speech in San Juan, Clinton described her strong support for representative democracy and final resolution of the status issue. "I want to reiterate…during my first term we will finally enable the status question to be resolved, based on the principles that government should be representative at all levels", she said. Both candidates indicated their respect for the status wishes of the island's 4 million residents. Clinton has supported Puerto Rico self-determination with her sponsorship in the Senate of the Puerto Rico Democracy Act of 2006 in the 109th Congress.