During the length of Dallas, J.R. certainly had his share of enemies that swore revenge on his character, and one enemy in particular took great pleasure in hitting J.R. where it hurt the most. But more on that later.

Cliff Barnes was the son of Digger Barnes, sworn enemy of Jock Ewing. That hat just got past from generation to generation. Cliff worked as a lawyer for a law firm in Dallas, and had some trouble with women. Not that he was any type of snake, but the death of his lover Jenny Ames caused Cliff's heart to close up.

J.R. discovered the reason for the death of Jenny, and he used that reason to prevent Cliff from winning an important election. Ahhh, but the story had two sides, as Cliff was able to seduce and conquer Sue Ellen, the unhappy and bitter wife of J.R. In the 5th season of the series, Cliff had another romantic encounter with her and proposed marriage, but Sue Ellen returned to J.R. for a second marriage.

Cliff was named the Chief of Office for Land Management in the state of Texas, and one of his goals was to destroy Ewing Oil. He began his quest by denying permits for new drilling sites and continued his path of revenge by shutting down drilling wells already in operation.

In 1979, Cliff was voted Man of the Year by the Dallas Civic Group and used this platform to make a run for Congress. Somehow, J.R. found his way into derailing his campaign, and Cliff Barnes was in more trouble than he cared for. Yet, in 1980, he was given a position as Assistant District Attorney for Dallas County.

Cliff had the final laugh with his old nemesis of J.R. when he gained control of Ewing Oil before the end of the series. In the final episode of the series, during the dream sequence of J.R., Cliff appears as President of the United States.