Face it, most politicians LIE about what they believe to get elected.
The reason it's so easy for them to fold... is because they are not folding. They are like brer rabbit saying:
Please Dont Throw Me In Dat Briar Patch!
They make a show of it to make it look like they tried to fight it and promise to fight on in the future, but in reality they are honestly relieved.
It is imperative in 2016 that we find someone who truly believes in conservative principles and is willing and able to fight for them.
Cruz definently fits that bill, and possibly Walker.
The rest either are pretending and dont truly believe, or are unwilling or in the case of someone like Perry unable to competently fight for them.
The Donald is just a joke and a distraction.