Is it permissible for Muslims to invite the non-Muslim ruler (president, king, etc.) to deliver a speech inside the Musjid?

Answer

It is not permissible for even a Muslim without wudhu to enter the Musjid. To a far greater degree will the prohibition apply to a non-Muslim who is perpetually in the state of ceremonial impurity (najaasat), namely, janaabat and kufr. Those who are guilty of allowing this commit a major sin. Being a president of a king does not purify a man from these states of ceremonial najaasat. If circumstances compel such an 'invitation', it will be imperative to insist that the president/king first takes a full shower ( a valid ghusl) to eliminate the physical janaabat. But this partial purification (i.e. only the physical dimension) does not rectify the spiritual pollution of kufr. The Qur'aanic prohibition is two dimensional – physical and spiritual (janaabat and kufr). The Qur'aan prohibits the entry of non-Muslims into a Musjid on the basis of these two grounds. However, we say with much trepidation that if there is a real need for extending the invitation to the president/king to speak in the Musjid, then at least he should be in the state of physical Tahaarat. And Allah knows best.