On “Dallas,” J.R. and John Ross are the bad guys and Bobby and Christopher are the good guys, right? Not always.

During the original show’s sixth season, when Jock’s will pits J.R. and Bobby against each other in a contest for control of Ewing Oil, Bobby becomes obsessed with beating his oldest brother. Bobby’s preoccupation is rooted in his longstanding desire to please his daddy, but he also wants to ensure his newly adopted son Christopher doesn’t lose his share of the Ewing empire.

At one point, Bobby finds himself using J.R.’s own tricks against him when he hires a prostitute to frame George Hicks, a corrupt government official whom J.R. has bribed in a complicated scheme to get a leg up in the contest. Of course, this is Bobby Ewing we’re talking about, so his trickery ends up taking its toll on his conscience. After Hicks tells Bobby that he’s “just as dirty” as J.R., Bobby comes home to Pam and confesses his sins. Unfortunately for him, Pam isn’t very sympathetic. “You would do anything to beat J.R. Anything!” she screams.

Flash forward to 2013. When J.R. dies, Cliff tries to steal Christopher’s deal to fuel the city’s municipal fleet, prompting Christopher to break bad, just like Bobby did three decades earlier. Christopher frames Alison Jones, the government official in charge of the contract, by arranging for John Ross to seduce her while Bum secretly photographs the encounter. After Christopher confronts Alison with the incriminating pictures, he goes home and reveals his scheme to Elena, who is aghast to discover the man she loves has stooped to blackmail. “Is this how you keep peace in the family — by turning into John Ross?” she shouts.

This scene bears more than a passing resemblance to the earlier version with Bobby and Pam. Before Bobby confesses his sins to Pam, he knocks back a glass of booze, just like Christopher does at the beginning of his conversation with Elena. Both scenes also depict the women decrying her man’s loss of morality. (Pam: “The Bobby I love would rather be dead than blackmail Hicks or anybody else.” Elena: “Christopher, you’re the most decent man I know and now you’re blackmailing people.”) The two scenes are also staged similarly, with both couples conversing in the bedroom they share at Southfork.

There’s also a major difference between the two sequences: Although Bobby tries to justify his actions to Pam, it’s pretty clear he’s consumed with guilt — unlike Christopher, who seems rather boastful about his blackmail scheme. Perhaps this is because Christopher’s motivation differs from his father’s. While Bobby wants to win the contest because he sees victory as a means of honoring Jock and preserving his son’s inheritance, Christopher seems to see his victory as a form of self-validation. As he tells Elena, “I’m not going to apologize for winning.”

It’s also worth pointing out that neither Bobby nor Christopher are squeaky clean in the first place: During the original “Dallas’s” fourth season, Bobby turns the tables on Sally Bullock when she cooks up an insurance scam with J.R. Similarly, during the TNT show’s first season, when Christopher uncovers video of John Ross and Marta del Sol’s tryst, he tries to blackmail him into ratting out J.R.’s role in the plot to seize Southfork.

The question is: What happens next? After Bobby’s ventures into dark territory during the 1980s, he returns to the straight and narrow, with only a few detours in the ensuing years. (See “Master plan, J.R.’s”). Christopher, on the other hand, seems poised for an extended stay on the dark side — if the promos for the TNT show’s third season are any indication, that is.

‘You Would Do Anything to Beat J.R.’

Unsympathetic

In “Crash of ’83,” a sixth-season “Dallas” episode, a sullen Bobby (Patrick Duffy) enters his bedroom late at night and sits in a chair while Pam (Victoria Principal) reads in bed.

PAM: [Unsympathetic] You look terrible.

BOBBY: Nothing like a celebration to really depress me.

PAM: I don’t understand.

BOBBY: You know that guy, Hicks? On Donna’s commission? J.R. had him bought and paid for. And I pulled a little number on him.

PAM: [Concerned] What do you mean?

BOBBY: I got down in the mud, honey. Just like I said I could. I forced him to change his vote on the variance.

PAM: What did you do?

BOBBY: I blackmailed him. I feel so dirty. [Rests his head in his hand]

PAM: [Puts down her book, leans forward] What do you want from me? Sympathy? Because you’re not going to get it.

BOBBY: Pam, I don’t want your sympathy.

PAM: Oh, yes you do. You want me to slap your wrist and then reassure you that you’re still the same wonderful man underneath it all. Well, I’m not going to help you out. You can stay dirty.

BOBBY: You don’t understand.

PAM: Understand? I understand that you’re not the man I married! The Bobby I love would rather be dead than blackmail Hicks or anybody else, double-cross the cartel and force his own mother into court.

BOBBY: [Exasperated] There were reasons.

PAM: [Screaming] Reasons? There’s only one reason! You would do anything to beat J.R. and get the company. Anything!

‘Is This How You Keep Peace in the Family — By Turning Into John Ross?’

Unmoved

In “Ewings Unite!,” a second-season “Dallas” episode, Elena (Jordana Brewster) enters Christopher’s bedroom, where Christopher (Jesse Metcalfe) is seated at the foot of the bed, drinking.

ELENA: Hi. It’s a little early for a drink, isn’t it?

CHRISTOPHER: I’m celebrating.

ELENA: [She sits next to him, kisses him and grabs the drink. She takes a sip.] What are we celebrating?

CHRISTOPHER: Barnes Global got to the head of the DCT. He tried to undercut my deal. So we had John Ross do what John Ross does … and we got pictures. [Christopher takes back the drink.]

ELENA: [Concerned] What are you going to do with the pictures?

CHRISTOPHER: [Takes a sip, rises] I already did. Alison’s married, and her husband’s a state senator — a real family values guy. And once she saw what I had, she decided to see things my way. [Takes a sip]

ELENA: [Mortified] You blackmailed her.

CHRISTOPHER: I made her keep her word.

ELENA: This is why I wanted out of the company. [Rises, walks toward him] Christopher, you’re the most decent man I know and now you’re blackmailing people.

CHRISTOPHER: She brought it on herself.

ELENA: Is this how you keep peace in the family — by turning into John Ross?

CHRISTOPHER: I am not John Ross! OK? I know I crossed a line here.

ELENA: [Glances down] That’s what breaks my heart. You did it anyway.

CHRISTOPHER: You know why I did it? My uncle J.R., he did a lot of bad things in his life. But he knew how to win. And I’m not going to apologize for winning.

ELENA: I love you. But I will not be a part of this. I’m going into business with my brother to drill our land. You may not like it, but I hope you understand.

CHRISTOPHER: I love you too.

How do you feel when Bobby and Christopher break bad? Share your comments below and read more “Dallas Parallels.”