U.S. now faces an even greater challenge with its extraordinarily high debt levels. While government regulators have long used interest rates and debt to influence the economy, these tools are less effective today. The slow growth in energy supply, coupled with rising debt, leaves the economy fragile and vulnerable. Without sufficient energy to fuel growth, the economy could face a downward spiral, similar to the economic collapse of the 1930s, possibly leading to a prolonged period of stagnation or worse.