Optimal (Or Just Effective) Strategy For The Resistance?
If you're a Resistance member and the first leader, this tactic gives a 1-in-5 chance of directly winning the game:

On the first round, send yourself and someone who isn't to your left. If both the player you send and the player to your left are Resistance members, you win!

The flow is as follows:


You and the selected Resistance member succeed at the first mission.
When the player to your left becomes the leader, she adds herself to your successful team, and you succeed at the second mission.
The third leader has to send the three of you on the third mission lest he out himself as a spy. You three keep down-voting missions until you get sent and succeed at the third mission.


To see that this gives a 1 in 5 chance of outright winning, multiply the probability that the player to your left is in the resistance by the probability that you successfully pick a resistance member for the first mission:

3/6 * 2/5 = 1/5

If the first mission fails, at least you know for certain the identity of one of the spies (and hopefully can convince your allies of this).

If the first mission succeeds and the second fails, well, now you're playing a normal game of the Resistance.

If the first two succeed and the third fails, you've almost won, and the Imperial spy gained almost nothing from waiting.

In each case, attempting the auto-win didn't cost you anything.