Leftists don't stand on principle against favored party elites (like Barack Obama now and Bill Clinton before him) because the Left HAS no principles to stand on.
A Republican is accused of looking sideways at a woman and it's sexual harrassment. A Democrat is caught in flagrante delicto with an employee, and no one bats an eye.
A Republican fights a war, and America is a terrorist nation. A Democrat fights a war and he's a hero.
A Republican administration is accused of using NSA files, and it's invasion of privacy, and 4th Amendment violations. A Democrat uses NSA files and it's protecting national security.
A Republican supports businesses, and he's "a friend of big business special interests." A Democrat supports businesses and he's "supporting workers or green energy or helping the economy."