Not having a single person be the executive likely helps. In a parliamentary democracy, the prime minister would have to tell the justice minister to do this. The justice minister would likely refuse. The prime minister’s recourse would be to fire the justice minister and get a new one appointed, but that’s a big step. Assuming that’s overcome, the new compliant justice minister would have to tell the public prosecutor to do it. In many countries that’s an independent office, and the justice minister wouldn’t have much standing. So you’re back to trying to fire people, and the petty vindictive prosecution is turning into a government-ending event; the PM is likely to be seeking alternative employment…
Executive presidency/governor systems, like those used in the US, have a generally higher dependency on individuals behaving properly.