Unless Congress acts, interest rates for government subsidized student loans will double to 6.8% from 3.4% on July 1. In May, House Republicans passed a bill that would index rates on new loans to the rate on 10-year Treasurys (currently about 2.6%), plus 2.5 percentage points, with an 8.5% cap. But with little Democratic support in the Senate, that bill is dead in the water.

Most Democrats want to lock the current 3.4% rate in place for two more years while Congress debates a "fairer" solution. Massachusetts Sen....