I thought about Leia's role in the Star Wars movies while I was proposing new SideShow figures of her (Endor Poncho, red Bespin Gown).
So this is what Leia does in Star Wars:
- she got the stolen plans to Obi-Wan Kenobi by hiding them in R2-D2
- they were eventually delivered to the Rebel base on Yavin 4 (because of R2-D2's persistence) and the Rebels were able to blow up the Death Star.
- Leia DID NOT help here. She fell into Darth Vader's trap but she did fight her way out of it after causing great duress to Han Solo that would take many months to settle (with Boba Fett and Jabba the Hutt).
So in conclusion, Princess Leia did NOT contribute to the cause in Empire Strike Back
- she infiltrated Jabba's and unfroze Han
- she killed Jabba the Hutt
- she, with C-3PO's help, and notably Luke's, nurtured the allegiance of the Ewoks so the Rebels won the Battle of Endor