I'll be fairly straightforward with you my friend: as stated before me, doing this publicly ain't the best way to get your protectorare through. I believe that if you really want an alliance, then you should fight and strive for it - through various plans and deals such as recruitment, internal and foreign affairs, as well as military - and with a solid answer to those four fields and two plus more folks in your alliance, you may have gotten to the starting point, and only after reaching this first solid ground will you be able to get a protecting force.
If you, however, can flex your goals a little bit, I'd recommend you join an alliance.
I sure hope you stay with Politics&War and wish you the best of luck on your ventures.
C.