Zig Zagged: The king, in a moment of jealousy, sends his greatest champion on a suicide mission. Almost as soon as he's left, the king rethinks things - the guy is the cornerstone of his army, after all. Just as he prepares to recall the hero, he receives the news that the battle is lost. He's overcome with remorse, but cheers up when he sees his chance to romance the widow. Then he discovers that the hero actually won the battle, but realised he'd been set up and sent the message as a decoy while he prepared his assault on the king...
Averted: The king puts business before personal disputes, and sends the hero wherever he'd be most tactically useful. If he wants him dead, he'll send an assassin to kill him in his sleep.
Enforced: The writers want the hero on a Suicide Mission on the front lines for dramatic effect, but he's too valuable to be risked. Unless of course the king wanted him dead...
Lampshaded: "Ooh, look - I'm in the front row again. Surprise, surprise."
One of the hero's rivals keeps dropping hints to the king about how dangerous these battles can be, and how you never know who could end up tragically dying...
The Death Seeker hero mentions how risky the mission is as reverse psychology, knowing the king would rather deprive him of the glory of command.
Exploited: The king's enemies spread rumors about the king's betrayal of the hero, building the hero up as a martyr.
Defied: The king, despite hating the hero, is too conscious of his responsibilities to betray one of his subordinates, and puts the notion aside.
Discussed: "Try to keep on the king's good side, or you'll find that you've been volunteered for a heroic death in the next battle."
Conversed: "It's amazing kings try that tactic all the time. Don't they know the hero's going to succeed and be more popular than ever?"
Deconstructed: No-one is fooled by the ruse. The king's other champions take note of what happens to you if you get too successful, and keep their heads down as much as possible, causing the war to take a turn for the worse. Their mistrust of him as a leader cause them to conspire against him in favor of his most promising rival, thus making the (miraculously surviving) hero's ascension a Self-Fulfilling Prophecy.
Reconstructed: The king is keenly aware of his subordinates' backstabbing tendencies and uses this tactic to avert Klingon Promotion. As they have to raise and equip their own armies, even a success will leave them militarily weakened in future. In cases where the hero's death is particularly necessary, he arranges for Unfriendly Fire to ensure it happens.
Played For Laughs: The hero parlays with the enemy general, and they realize they've both been sent to die by their own leaders. They get drunk together and spend hours moaning about how their kings don't appreciate them.
Played For Drama: The hero sets off and dies. The entire kingdom is devastated... except for the king. Eventually, though, the king realizes how stupid he's been when he's told that the hero was one of the most important members of the kingdom.