What is the ruling on one who calls people to worship other than Allah, whether he believes in what he calls to or not, and whether he worships what he calls to or not, and is he considered a polytheist?

Inviting others to worship other than Allah is major disbelief that expels one from the fold of Islam, regardless of what the inviter intends, whether the inviter believes in what he is inviting to or not, whether he is serious or joking, and whether his invitation is accepted or not. The mere act of inviting to disbelief is considered disbelief. It is stated in "Tabyeen Al-Haqa'iq" by Az-Zayla'i Al-Hanafi: "And enjoining disbelief is disbelief." We emphasize that this is a clarification of the ruling on the action, that it is disbelief, and not a judgment on a specific person. Judging a specific person requires the fulfillment of conditions and the absence of impediments.