Hillary Clinton's running mate Sen. Tim Kaine reiterated his long-standing belief on Sunday that the administration does not have the legal authority to conduct strikes against the Islamic State, but he failed to bridge the difference of opinion with the Democratic nominee.

Kaine fielded a question on "Meet the Press" about the president's recent decision to begin airstrikes against the Islamic State in Libya. The Virginia Democrat said that all strikes against the Islamic State are against the law as long as Congress fails to pass a new authorization for the use of military force.

"I do not think we should be in an offensive war against ISIL without congressional authorization. That's been my long-held position," Kaine said. "And Secretary Clinton has said Congress should do its job instead of hiding under their desks and have a debate and have a vote on military action against ISIL."

The administration is currently conducting strikes under authorizations from 2001 and 2002 that allow military action against al Qaeda and associated forces and in Iraq, respectively. Several attempts to pass a new authorization specific to the Islamic State have stalled on Capitol Hill.

Clinton said during a debate last year that she believes the administration has the right to carry out the strikes under current authorizations, but she also said she supported congressional action on a new authorization.

Asked about his difference of opinion with Clinton, Kaine said the two actually have the same goal of a new authorization for the use of military force.

"I have very grave doubts about whether the legal authorities currently in place allow us to wage an offensive war against ISIL. But Secretary Clinton and I get to exactly the same spot, in that Hillary has said — now this probably goes back six or eight months now — that Congress should finally own up to its responsibility, that is the most solemn responsibility in Article I of the Constitution, to authorize this military action," he said.