Obama.
If it can be shown he is not eligible, his mega backers will remove him in hours.
He will never send the doc from HI straight to the NYtimes etc.
And I assume that he also changed other information, information that would have shown he was not eligible. And somehow, the people in Hawaii who sent the two copies didn't notice these modifications in the released document, or else are part of the conspiracy, meaning it's not one person.
And Barack did this on the computer he has hidden in his office, where none of his advisors would know, and hid the oroginals from his wife and advisors and others (because you said he was acting alone).
And what do you think was on his original certificate that he had to modify? Hawaii has certified that he had a birth record, and they sent it to him, so it can't be that he doesn't have a birth certificate from Hawaii. It could be the information that his father wasn't a citizen, except the one he released shows his father wasn't a citizen, and he's always said his father wasn't a citizen, and we all knew that his father wasn't a citizen, and have debated what they means for two years.
So since he didn't modify the part that raises questions, what part did he modify?