Forgot I Could Change the Rules

"King Jaffe Joffer: Who am I to change things? Queen Aoleon: I thought you were the king."

- Coming to America

Bob has near absolute authority in his land, but an existing law will hurt him or someone he loves. Often this law forces an Arranged Marriage, other times it can be a minor crime treated with a draconian punishment, or it might be something else.

Bob agonizes about how helpless he is to change this law, until he remembers, or is reminded, that he does have the authority to change the law.

Now this might come across as What an Idiot! for Bob, but Bob was raised to respect tradition. So actually using his authority this way didn't occur to him until just then. Especially when it is a normally good rule that works out badly in this case; this is a traditional reason for the existence of pardons.

Now in reality, some rules were out of the reach of all but the most absolute monarchs. Rules that could have been changed would also be met with resistance unless the ruler was strong willed enough to enact these changes. Sometimes fiction will deal with these difficulties as well, but not always.

Contrast Screw the Rules, I Make Them (Bob can enforce, and even change, the rules; he just chooses to ignore them).

Anime and Manga

 * Princess Knight: Sapphire's father realizes this at about the two-thirds point in the anime. Just as he's about to release a proclamation that would allow women to rule Silverland, he is by apparently complete coincidence kidnapped by the baddies, who have gotten tired of waiting for Sapphire to slip up and reveal she's actually a girl.
 * Sword Art Online: This is the downfall of the Big Bad of the second story arc, . Despite conducting his research within a virtual world where he had administrative access that allowed him to alter the world as he wished, he could only think in terms of conventional security (such as constructing a cage accessed by entering a password, rather than allowing entrance and exit only to himself).

Film -- Animated
"Sultan: "It's that law that's the problem... well, am I Sultan or am I Sultan? I decree, from this day forward, the princess may marry whomever she deems worthy!""
 * ''Aladdin: At the end of the film, the Sultan falls into this in regards to the "princess must only marry a prince" law.

Film -- Live Action

 * Coming to America
 * RoboCop: Averted. When the vice president of OCP takes the president hostage, Robocop cannot intervene against an OCP employee. Instead of changing Robo's directive, the president just fires the VP, making him fair game.

Literature

 * The Bible: Averted in the Book of Esther, the king is maneuvered into creating a law that would allow all the Jews to massacred by Haman. When Queen Esther reveals that she is Jewish herself and exposes Haman to the king, the law authorizing pogrom cannot be annulled by even the king. However, there is nothing that prevents him from passing a new law enabling the Jewish population to defend themselves with state support.
 * Incarnations of Immortality: Played with. In the first novel, it isn't so much that Death forgot that he could change the rules; it's that he didn't know that he could (in fact, he didn't even know half of them), causing infant souls born under questionable circumstances to go to Purgatory and later triggering . At the end of the book, he realizes that it's his prerogative to do what he damn well pleases as the Incarnation of Death,   The last is retconned in later books, as Death is acting outside of his authority.
 * The Once and Future King: Inverted. King Arthur chooses not to change the law about burning adulterous wives after Guinevere's affair with Lancelot is revealed. He is not (particularly) jealous of them. He loves Guinevere, he loves Lancelot, he is the king and the law is barbarous, but he chose not to change it for the reason that nobody should be above the law.
 * Also, he pretty much ignores the two of them until he can no longer pretend to be ignorant of the affair, and allows the two to flee. He's very much a tragic figure, though, as he does have to persecute them. His character arc of the last book or two has been realizing that the law needs to apply to everyone.
 * Twilight series: In Breaking Dawn, Jacob has to submit to the will of Sam, the Alpha Wolf. When Sam orders him to help destroy the Cullens (and Bella), he remembers that he was born to be the Alpha but he had voluntarily given up the birthright. Choosing to become the Alpha frees Jacob from obeying Sam's orders.

Live-Action TV
"The Doctor: The laws of time are mine! And they will obey me!"
 * Doctor Who: Inverted. The Doctor really can't change the rules, at least without causing seven kinds of hell to break loose, but he temporarily forgets this.

Theatre
"Lord Chancellor: Victory! Victory! Success has crowned my efforts, and I may consider myself engaged to Phyllis! At first I wouldn't hear of it -- it was out of the question. But I took heart. I pointed out to myself that I was no stranger to myself; that, in point of fact, I had been personally acquainted with myself for some years. This had its effect. I admitted that I had watched my professional advancement with considerable interest, and I handsomely added that I yielded to no one in admiration for my private and professional virtues. This was a great point gained. I then endeavoured to work upon my feelings. Conceive my joy when I distinctly perceived a tear glistening in my own eye! Eventually, after a severe struggle with myself, I reluctantly - most reluctantly - consented."
 * Iolanthe: A comedic version of this occurs. The Chancellor wants to marry Phyllis, who is his ward.


 * A song or so later, Iolanthe's life stands forfeit for breaking her vow not to reveal herself to the Lord Chancellor, and so do the rest of the fairies' -- all save the Queen—for marrying mortals just as Iolanthe did. It takes the Lord Chancellor's brilliant legal mind to save the day by changing the fairy law to mandate death for any fairy who don't marry a mortal. Hasty marriage for the Queen, and everyone goes home happy.