Sen. Rand Paul (R-Ky.) is out with a brief statement on the situation in Syria, calling for a cautious approach and congressional approval for any military action.

Sen. Rand Paul (R-KY) listens during a news conference with other Senate Republicans to announce a proposed balanced budget amendment to the Constitution in the U.S. Capitol on March 31, 2011 in Washington, DC. (Photo by Brendan Hoffman/Getty Images) Sen. Rand Paul (R-Ky.) (Photo by Brendan Hoffman/Getty Images)

He also appears to question the administration's assertion that the Syrian regime definitely used chemical weapons. Vice President Biden has said there is "no doubt" that it did.

"We should ascertain who used the weapons and we should have an open debate in Congress over whether the situation warrants U.S. involvement," Paul said. "The Constitution grants the power to declare war to Congress, not the President."