Rand Paul threatens to block Yellen nomination

Sen. Rand Paul, R-Ky., will block the nomination on the Janet Yellen to become the chair the Board of Governors of the Federal Reserve unless Senate Majority Leader Harry Reid, D-Nev., agrees to allow a vote on his own legislation to audit the Fed.

"The American people have a right to know what this institution is doing with the nation's money supply. The Federal Reserve does not need prolonged secrecy--it needs to be audited, and my bipartisan Federal Reserve Transparency Act will do just that," Paul said in a letter released Tuesday night.

The Federal Reserve has long been a target of both Paul and his father, former Rep. Ron Paul, R-Texas, who advocated abolishing the institution. This is also not the first time Paul has blocked the president's nominees. In March, he filibustered the confirmation vote of John Brennan, who was nominated to run the Central Intelligence Agency, to protest the expanded use of drones.

Meanwhile, Sen. Lindsey Graham, R-S.C., has threatened to block the president's nominees unless survivors of the 2012 attack on the U.S. consulate in Benghazi, Libya are allowed to testify before Congress.

Senate Republicans and Democrats have clashed several times this year over nominations, with Reid threatening to use theso-called "nuclear option" to change the Senate rules and limit the minority party's power to block nominations. Reid was able to cut a deal with Sen. John McCain, R-Ariz., to avert such a drastic measure.