I believe that there are specific restrictions placed on a ger (convert) being a legal decisor on a beit din. What are these restrictions and do those, ipso facto, preclude that individual from receiving smicha yadin yadin?
A convert can:
- Judge a case as part of a beis din that has been accepted by the Yisrael
- Force a judgment on another convert
- Force a judgment even on a Yisrael if the converts mother or father was born of a Yisrael
A pure convert cannot:
- Force judgment on another Yisrael
These laws are based on the double language of שׂוֹם תָּשִׂים עָלֶיךָ מֶלֶךְ, אֲשֶׁר יִבְחַר יְהוָה אֱלֹהֶיךָ בּוֹ, any appointments should be restricted to the law of kings. One law is that he must be kin - מִקֶּרֶב אַחֶיךָ, תָּשִׂים עָלֶיךָ מֶלֶךְ--לֹא תוּכַל לָתֵת עָלֶיךָ אִישׁ נָכְרִי, אֲשֶׁר לֹא-אָחִיךָ הוּא. The Shulchan Aruch allows a convert the same status of a Yisrael if his mother or father had a Jewish parent, as this can still be called "your kin".
These laws are based on Shulchan Aruch CM 7:1 and the Shach and Sema there.