Can you commit a card to the force even if it is already focused. Example: a nightsister is focused, can you still commit it to the force and have its abilty go off to damage an objective? Or another example: can you commit a focused force wraith and still count its icons in the force struggle?

Thanks.

Yes, you can commit a card to the force even if it is focused; however, normally it will not contribute its force icons to the force struggle while it is focused. But in your example, nightsister's effect still can be triggered.

Nice. Thanks.

Another situation where you might want to commit an already focused unit is if you're light side and your opponent is running Ghosts of the Dak Side, to protect your big guns from Force Shockwave.

And occasionally, committing a focused Luke is a good play to put some pressure on the DS as Luke will be ready during their turn and could take the force for you at the end of their turn if he stays out of engagements.

And occasionally, committing a focused Luke is a good play to put some pressure on the DS as Luke will be ready during their turn and could take the force for you at the end of their turn if he stays out of engagements.

That's fun to do. I also don't mind dropping http://www.cardgamedb.com/index.php/starwars/star-wars-card-spoilers/_/the-hoth-cycle/a-dark-time/unwavering-resolve-a-dark-time-48-5

every once in a while to win a force struggle with my exhausted units on either my turn or my opponent's... the trick is to make sure you pick a unit that is not committed to the force, as that is a requirement stated on the event card.