Worry, anxiety and nervousness are at an all-time high in American society. The economy, terrorism, politics, work, parenting — the list of stressors is endless. But author Ruth Whippman believes there’s another reason why anxiety has become the new normal for Americans, and it has to do with the notion that happiness must be pursued above all else. The concept is even baked into the Declaration of Independence. Whippman recently joined the Knowledge at Wharton show on Wharton Business Radio on SiriusXM channel 111 to discuss her new book, America the Anxious: How Our Pursuit of Happiness Is Creating a Nation of Nervous Wrecks . An edited transcript of the conversation follows. Knowledge at Wharton: A state of perpetual anxiety does feel like a new norm right now for most Americans. Ruth Whippman: Absolutely. The World Health Organization says that America is the most anxious country on the planet and by a wide margin. A second-place country is very far down the list from America.…