Jefferson owned a copy of the Koran, because he felt it the best way to learn about the "Muslim terrorists" of the day - Barbary Pirates. They, too, were Wahhabi-type (radical) Muslims.
Jefferson used his copy of the Koran much like a textbook. It gave him insight into their political and social agendas, as well as their social hierarchy. It is from that book, that he gleaned the information he found necessary to deal with the Pirates.
As for Keith Ellison, yes, he's Muslim. There is absolutely nothing wrong with that, so please get off your pious high horse.
Just as some Christians did and still do wrong or bring harm to others in the name of their radical religious beliefs (oh..how about those Crusades?) you find peoples of all religions doing what they feel is right, based upon their religion. Where we have a problem, is when people take 'The Word' too literally and bring harm to others.
Now...I'm going to do my best to not go into the religious debate here. But I will say that there is absolutely NOTHING wrong with being Jewish, Muslim, Hindu, Taoist...or any other religion in this country. It's important that YOUR religious beliefs work for YOU. People have no place in inflicting their religious beliefs on others. It's all about FREEDOM OF RELIGION here, folks. (Not to mention, freedom FROM religion.)