The Senate yesterday failed to advance a bill to lower interest rates on federal student loans for another year. Last week, interest rates on federal student loans doubled from 3.4 percent to 6.8 percent. The measure taken up yesterday would have returned rates on newly-issued loans back to 3.4 percent for one more year. But the Senate came up short on the 60 votes needed to proceed with the bill. While both Democrats and Republicans are in favor of lower rates, they disagree over whether or not to tie the interest rates to financial markets. If they can’t hash out a compromise, the raised rates will affect the seven million people who will take out a student loan this year.