The top Republican on the Senate Foreign Relations Committee argued against implementing a no-fly zone over Libya on Thursday, and also said that Congress must pass a formal declaration of war if the Obama administration decides to take that step.

"Clearly, the United States should be engaged with allies on how to oppose the Qaddafi regime and support the aspirations of the Libyan people," said Sen. Richard Lugar (R-IN) at the start of the committee's Thursday morning hearing on the Middle East. "But given the costs of a no-fly zone, the risks that our involvement would escalate, the uncertain reception in the Arab street of any American intervention in an Arab country, the potential for civilian deaths, the unpredictability of the endgame in a civil war, the strains on our military, and other factors, I am doubtful that U.S. interests would be served by imposing a no-fly zone over Libya."