Why is that when a Republican screws up, he is called a RINO or "not a real conservative" ?

Democrats don't need to, they somehow get elected anyway... Hiliray Clinton and a host of other top Democrats stood up in front of the world to say that the US needed to invade Iraq... and they voted to give Bush the authority to use military force in Iraq... but somehow Bush was and still is the only one to get any blame for being wrong... somehow, Clinton, who screwed up, has since run for President, been re-elected as a Senator and is currently our Secretary of State... explain that to me...