Why didn't Grima....

[Inziladun]

Originally Posted by TheLostPilgrim

I forget if this is a film invention or not....But Grima held sway with Theoden, did he not? He had Theoden sort of under his control?

If so, why didn't he coerce Theoden into SIDING with Saruman--Having Rohan's armies join with Saruman's?

In the books, Wormtongue's influence over Théoden was not a secret. Gandalf made the remark that everyone except Théoden knew the man as "Wormtongue".

Saruman probably thought (correctly, I believe) that inaction by Théoden would be enough to allow him to accomplish his goals, and that an overt alliance with him would have met with enough resistance from both the military and the commoners to have made it difficult to enact. Wormtongue would likely have been turned out, if not killed. Walking the fine line that he did served Wormtongue's purpose, without needless risk.