The Grumpy Celt said:
But how, as a DM, do you maintain controll over the trail without determing the verdict and the course before hand?
If you like to have the DM be the one who resolves social conflicts, then it's okay that he has control.
If you don't like that, use the results of dice. How would you use the dice?
Simple case. For each witness/testimony/objection!/whatever, make a check:
- For actual legal eagle stuff, use Knowledge (whatever law you're working under - Religion, Nobility, Local) for the skill.
- For dramatic speeches, use Diplomacy.
- For lies and falsehoods, use Bluff.
- To suss out a lie, Sense Motive.
- To incite someone to admit guilt, use Intimidate.
DC of the checks should either be an Opposed roll, against the other lawyer, or against a set DC representing how difficult it is to sway the jury or judge trying the case.
At the end of the trial, make a Verdict Roll that sums up your case. What skill was most important in the trial? What skill did you roll the most often? Make a check as the Verdict Roll.
Most of the rolls should impact on future rolls. Making your defendant look sympathetic to the jury - +2 to the Verdict Roll. Destroying the opposition's prime witness - -2 penalty to their Verdict Roll, or lower the DC by 2. etc. You get the idea.
Success on the Verdict Roll = you win; failure = you lose.
You can also have a degree of success that might determine sentencing, "the trial was a sham" feelings by the public, or whatever.
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Another option would be to stat up the trial as a monster, give it hp and damage, saves, skills, and feats, and let the players "battle" it out.