There is no neck to neck if Hillary Clinton wins by big margin in Texas and Ohio next Tuesday, she will be the nominee period if this happens and without any fight at the convention.
I think Obama is far more calculating than Hillary. He got where he is by dirty politics. His goes on behind the scenes, though, where Hillary is more out in the open. Obama’s brand of dirty politics is more dangerous. He looks good while he forces Hillary’s hand and makes her look like a nagging shrew. Something that everyone hates. He will do the same thing to McCain. He will make him look like a grumpy old man without ever having to say it. I have heard rumors that there was some pretty serious threats against some of the black delegates to switch to Obama. I really think Obama plays very dirty.