The current governmental structure was established under the Constitution of the Commonwealth of Puerto Rico, ratified in 1952. Sitting governor Luis Muñoz Marín was re-elected as the first governor under the Constitution. Under Article IV of the Constitution, the governor continues to be popularly elected every four years and is the head of the Commonwealth's executive branch. The governor-elect takes office on January 2 of the following year in a public inaugural ceremony which may be preceded by a private oath-taking ceremony.