Cheney an example for democrats

Last week Dick Cheney was all over the news with President Obama.
He dared to speak after him about national security defending the previous administration and presenting, justifying his views. Well I have to say that I don't agree with him but I think it is a lesson that democrats should learn when they are in the opposition. During the Bush years they did not speak up even though there were many things to talk about,WMD,torture,social security...
They were quiet, why Cheney should follow this bad example?