Without a doubt, the most significant threat to our economy is the burgeoning student loan debt crisis. While we can't agree on a way to solve the problem, we must agrees that for America to stay competitive in a global economy is to have the best educated populous in the world.
Eliminating the income cap on the student loan interest deduction would be hugely beneficial. Those who go on for upper level degrees like JD, MD, PhD, etc, may end up making more money than others, but also tend to have significantly higher student loan debt. However, under current law, these earners cannot contribute more to the economy because much of their income is tied to loan payments. The ability to deduct the interest would greatly ease the burden and free up thousands to spend in the economy.