Currently, there exists a question regarding straightedge only constructions; however, my specific question pertains something that is not found in that thread, and I do not think it will be answered any time soon for that matter.
Foreplay aside, my question centers around the following simple fact:
Given a circle $\Gamma$ and a point $P$ outside of $\Gamma$, it is possible to construct the two tangent lines from $P$ to the circle by straightedge alone, using the straightedge only construction of the polar line.
My question is - where can I find a proof (or perhaps, could I be supplied with one) that this construction works?
Thanks in advance for any assistance. This is not homework, just mere curiosity.