A federal judge on Thursday rejected a constitutional challenge filed by two former lobbyists with a pro-Israel group who are charged under a World War I-era espionage law with receiving and disclosing national defense information.

Lawyers for the two former lobbyists with the American Israel Public Affairs Committee argued that the 1917 Espionage Act is unconstitutionally broad and vague, as it seeks to bar receipt or disclosure of "information related to the national defense" to "persons not entitled to receive it."

They also argued that prosecutors were out of bounds for using the statute in an unprecedented manner: prosecuting lobbyists who in the normal course of business discuss policy issues with government officials. The defense argued that lobbyists should not be held responsible if government officials leak sensitive or classified information to them.

But T.S. Ellis III, a judge in U.S. District Court in Alexandria, upheld the constitutionality of the law as well as the government's effort to apply it to the two lobbyists, Steven Rosen and Keith Weissman.

In a hearing in March, Ellis sharply questioned prosecutors about their uses of the statute and hinted that he had reservations about the law's constitutionality on free speech grounds.

In his 68-page opinion, Ellis wrote that "it is a hard case because it requires an evaluation of whether Congress has violated our Constitution's most sacred values ... when it passed legislation in furtherance of our nation's security. The conclusion here is that the balance struck between these competing interests is permissible."

The indictment against Rosen, of Silver Spring, Md., and Weissman, of Bethesda, Md., alleges that they conspired to obtain classified government reports on issues relevant to American policy, including the Al Qaeda terror network; the bombing of the Khobar Towers dormitory in Saudi Arabia, which killed 19 U.S. Air Force personnel; and U.S. policy in Iran.

The pair are accused of sharing the information with reporters and foreign diplomats.

A former Defense Department official, Lawrence A. Franklin, pleaded guilty to providing Rosen and Weissman classified defense information and was sentenced to more than 12 years in prison. Franklin has said he was concerned that the United States was insufficiently concerned about the threat posed by Iran and hoped that leaking information might eventually provoke the National Security Council to take a different course of action.

The 1917 law has never before been used to prosecute lobbyists, leading Ellis to conclude back in March that the case moved into "new, uncharted waters."