Karzai is riding a tiger. If he leaves the office he will be hanged on the nearest lamppost. What we see here is the new Gaddafi in the making.
We should hope a democratic movement against Karzai would get strong enough to remove him democratically.
Afghan democracy is of Mao style: "Power comes from the barrel of the gun." And why not? An insurrection is much easier to arrange than a popular, peaceful revolt. All you need is money to pay soldiers.
Also to remove someone from the office democratically that someone must adhere (willingly or not) to democratic rules. For example, he must not monkey with elections; he must quit if he loses; he must not stay in the office longer than the Constitution allows; and so on. Considering that Karzai's life is at stake, loss of the office means loss of his life (and his way of life too.) Perhaps he can escape Afghanistan and live somewhere, like in the USA, on money that he stole from the US aid. But he knows what the word "assassin" means, and he saw just a month or two ago how they work. He will not be safe anywhere on Earth.
While I am not defending Karzai, or anything he has done or anything he is doing, your statements are mere hyperbole. While anything is possible, neither Karzai's demise nor his safety are absolute or certain, no matter what happens.
I doubt you have more perfect knowledge of the situation or of the future than the rest of us, but most of the rest of us do not make such bold predictions and state them with such certainty. I won't pretend to know Karzai's future for certain; I'll let history write the outcome without my predictions.
No matter how ill any of us feel towards Karzai, the one positive that might be said for him is that there are worse figures than him in Afghanistan who would like to be in Karzai's place.
The Afghan political culture of the last two hundred plus years still sits atop all the modern political changes there of the last fifty years. It remains a country of tribes and villages where both tribal leaders and village elders have the sway of Mafia dons on culture and politics, no matter what political systems get put on top of it all. Just like our Mafia types, violence has always been a part of how the self-appointed village and tribal leaders insure their standing means their decisions will reign in the tribe or in the village. The Taliban didn't invent this, they were and are just more brutal and fanatical with it.
It's easy to attack Karzai for not changing all that, instead of succumbing to being a part of it, yet, short of a massive WWII style total takeover of the country by a few million outside forces (THAT was never going to happen) it is doubtful any Afghan leader was going to change it any time soon.
All that aside, none of it has required Karzai to take many of the "anti-American" positions he has taken (they have been neither in his interest or in the interest of Afghanistan) and none of that has required Karzai to be so inept at geopolitical diplomacy, when Afghanistan needs every friend that wants to be its friend and Afghanistan is only hurt by Karzai playing different friends of Afghanistan against one another.
That's why I say he's "crazy", the corrupt political culture of Afghanistan not withstanding.