A new constitution that takes effect Tuesday gives 2 million Haitians living abroad more rights in their homeland, including the ability to run for some posts in government.
The amendments were approved last year but Haitian President Michel Martelly blocked them at the time because of unspecified errors.
The new constitution also paves the way for new Senate elections that would give Martelly a chance to bolster his now-tiny bloc of supporters in the legislature.
He fired the nine members of a provisional electoral council by decree in December but the new constitution enables him to form a permanent electoral panel.
Martelly signed the amended constitution into law Tuesday at the National Palace as diplomats and lawmakers looked on.