They may or may not been written by him, but they were written either by him or by someone pretending to be him, and under his name, and sometimes with his signature at the end. To think that he never knew that newsletters which included things like how to shoot a black youth and not get caught, saying that MLK day is hate whitey day, 95% of black males in DC are criminals, the LA riots only stopped when it came time for blacks to pick up their welfare checks, and various other racist, homophobic, anti-semetic, and conspiratorial ideas too numerous to list were being sent out with his name on them seems absurd to me. The possibilities in my mind are this;
1) He wrote them and believes all those absurd and terrible things (this seems unlikely to me)
2) He didn't write them, but knew what was in them and did nothing because he agrees with those things (seems still unlikely)
3) He didn't write them, but knew about them and decided to do nothing because he thought it was good business to say these things
4) He didn't write them and had no idea what was in them
If 1 is true, he obviously is insane. If 2 is true, he is also insane. If 3 is true, he was willing to undermine his values to make money or gain popularity with racists, which is terrible. If 4 is true, he is not a very good leader and is probably not competent enough to be president. His claim now when asked about these is that he didn't write them, didn't know what was in them, and doesn't even know who did write them. In the past when asked about them, he didn't claim that he didn't write them, and defended their content to a certain degree. Personally my guess is somewhere around option 3.
Here's some scans of the newsletters in question for anyone who is curious
Anyway, there are other reasons I wouldn't personally vote for him.
