Puerto Ricans have voted against two constitutional amendments that would have limited the right to bail and cut the size of the legislature.
Governor Luis Fortuno and other political leaders argued the first change would help to tackle crime, and the second would save money.
But voters were unconvinced, rejecting the two proposals by about 55% to 45%.
In November, Puerto Ricans will vote on whether their country should remain a self-governing US territory.
The changes to the legislature would have reduced Senate seats from 27 to 17, and seats in the House of Representatives from 51 to 39.
Supporters of the proposal said the reduction would make the legislature more efficient.
But opponents said it would make it more difficult for minority parties to win seats.
Puerto Rico's constitution currently stipulates that every accused has the right to bail.
The amendment would have given judges the right to deny bail in certain murder cases, including those accused of premeditated murder, or killings committed during home robberies, sexual assaults or drive-by shootings.
Supporters argued this would help crime-fighting efforts as witnesses were often intimidated by suspects out on bail.
But opponents said restricting bail would disproportionately target the poor.
Puerto Ricans will head to the polls again on 6 November to vote on whether they want the current status as a self-governing US territory to remain.
Regardless of how they answer that question, they will also be asked to choose between three alternatives to the current status: statehood, independence or sovereign free association.
Any change would require approval by the US Congress and president.