Can a non-Jew (or a person studying for conversion, but not yet converted) lead prayers? Is there a difference for different parts or prayers (e.g. Kabbalat Shabbat vs Amidah)? Is there a difference if there is a minyan or not?

No, a non-Jew is not eligible to lead prayer.

 

Prayer within Judaism is not simply a voluntary, spiritual opportunity.  Rather, it is an obligation enshrined within Jewish law.  As a consequence, the prayer leader actually functions in such a way as to afford others the opportunity to fulfill their prayer obligation.  Many centuries ago, Jewish law ruled that only a person who is obligated to fulfill the commandment of prayer could provide others with the opportunity to fulfill their obligation:

 

“This is the general principle: One who is not obligated in a matter [of ritual observance] cannot enable others to fulfill their obligation [in that matter]." (Mishna Rosh HaShana 3:8)

 

Hence, since non-Jews (and prospective converts remain non-Jews until their conversion is complete) are not obligated in the ritual of prayer, they are not eligible to lead prayer.

 

Even beyond the legal issue, this makes sense.  After all, Jewish prayer involves particular Jewish affirmations, and Jewish approaches.  These affirmations, would – at a minimum – seem inconsistent coming from a non-Jew.  Consequently, there is broad agreement across the Jewish spectrum that prayer leadership in the Jewish context should be the domain of a qualified Jewish individual.

 There are different levels of prayers that carry different types of concerns. With any prayer that fulfills a requirement of the halakha, a non-Jew certainly cannot lead, since the prayer leader is, at least in part, fulfilling an obligation on behalf of those who are gathered. This is something that a non-Jew could not do because he does not share those obligations.

With other prayers there is no precise legal impediment since they do not represent the fulfillment of obligations. Nonetheless, as these have become part and parcel of the standard liturgy, they have become part of what we assume to be mandated when we talk about reciting daily prayers. We still think of the person leading prayers such as kabbalat shabbat as a shaliach tzibbur, a representative of the community. So leading such prayers is tantamount to leading the community prayer service, and I would consider it improper for a non-Jew to lead these parts of the service as well.

The gray area for me is in reciting non-liturgical prayers – English readings and the like – that we may incorporate into a service but are not fixed parts of the liturgy. Here in principle there is no legal relevance one way or the other to who leads such a prayer. Thus it becomes entirely a question of ethos and judgment, which may differ from one community to the next. Many authorities suggest that preserving the sanctity of the prayer service requires that no non-Jew ever lead a prayer. If there is occasion for a local official, clergy from another religious community, or some other non-Jew to address our community, these rabbis would argue that this must happen outside the framework of a service, even if we allow it in  the sanctuary.

For others, though, the mere notion of a non-Jew participating is not inherently problematic – the struggle is tied much more to whom we permit to participate. The biggest struggle is about the non-Jewish half of intermarried couples who often wish to come up to the bima (podium) for the parents’ aliya at a bar mitzvah or in some other way actively participate in a family simcha (celebration). Here there are two problems, both concerned with perception: we may be concerned that doing so suggests a kind of communal acceptance/embrace of intermarriage which we want to avoid; and allowing this creates a problem of marit ayin, of giving the false impression that the person is in fact Jewish since they are members of the Jewish family we are in fact celebrating. This is especially a problem since they have been members of a Jewish family for some time and have actively chosen not to convert. So the strength of the opposition comes largely from the problems of this case.

This leaves room, in my opinion, to be more open to allowing participation when such problems of perception are absent. Allowing visiting clergy to offer a greeting or even benediction appropriate to a synagogue does not risk confusion as to that person’s religious status. Giving someone studying for conversion the chance to participate in a marginal way could serve to applaud and embrace their efforts and process while preserving a clear distinction between Jewish and not yet Jewish. These could be opportunities to be inclusive without the blurring of boundaries between “in” and “out” that are essential to our own self-definition.