Can anyone logically explain how Iraq & Saddam Hussein were a threat to the U.S.?

They were not a threat. What they were was a thorn in the side of GWB. He was annoyed that Saddam was still in power for two main reasons. First, some people feel that, had his father gone into Baghdad and removed Saddam from power after the first Gulf War, it would have helped his chances of getting reelected. Thus, the younger Bush may have blamed Saddam for his father's failure. He also may have wanted to outdo his father by taking him out, but that's for the psychologists to discuss. The other, stated, reason, was that Saddam had wanted, planned or attempted to inate George HW Bush. Regardless of how much truth there is to that claim, it hardly seems a reason to plunge this country into war.