The ruling Liberal Democratic Party on Sunday rubber-stamped an internal rule change to extend the maximum tenure of its president from the current six years to nine, paving the way for Prime Minister Shinzo Abe to run for a third term that would last through 2021.

The revision, adopted at the party's annual convention, represented a crucial step toward the prospect of Abe becoming the nation's longest-serving prime minister.

What was supposed to be a triumphant moment for Abe, however, was somewhat marred by an ever-spiraling scandal that has dogged him and his wife, Akie.