Whether a flat tariff is ultimately the best trade policy for America is an open question, but it is worth considering the possibility simply because it sets a baseline, the "least we can do," for a solution.
The social contract requires that the government provide the environment necessary for its citizens to achieve reasonable levels of Life, Liberty and Happiness. Right now, the American government is in breach of contract.
The U.S. middle class's path of success ended precisely when the gold standard currency system was replaced by the floating-currency system in 1971. Prosperity is built on the foundation of a stable currency.