Palin is not running against Trump, and Trump is not running against Palin. Neither is running against Bachmann, and vice versa.
We could not have defeated Germany in World War II with just one General, or just one point of attack, or even one whole country. Our success against the NAZIs required many Generals, many deceptive operations, many fronts, several allied nations, a common recognition of "who the real enemy is", and a common determination to defeat that enemy.
Our common enemy today is a communist/muslim alliance that is hell-bent on the destruction of the USA specifically, and Western Civilization in general, and the worst of them are rooted among us, not "over there".
RINOs don't want to fight the enemy; they just insist on picking up the spoils from our destruction.