With the possibility of military action against Syria looming, constitutional scholars are debating whether the president must first get approval from Congress to legally launch an attack.

Congress has non-specific authority to “declare war” under Article I, Section 8 of the Constitution. But to John Yoo, a professor at the University of California Berkeley School of Law and prominent conservative, the notion that this means lawmakers must preapprove any attack is “a misinterpretation of the Constitution.”

Yoo pointed out that the United States has used force abroad at least 130 times, but Congress has only formally declared war five times in American history. “If President Obama wants to use force in Syria, constitutionally I think he can,” he said.

A top Justice Department official under George W. Bush, Yoo addressed the constitutionality of striking Syria on a conference call August 29 organized by the Federalist Society. He faced off against University of Virginia School of Law Professor Saikrishna Prakash, who took the opposite tack, arguing that the “‘declare war’ clause takes away any implicit grant of executive power that the president would otherwise have.”

Focusing on the “declare war” clause, Yoo argued, is misleading. “The most important provision is the rest of the Constitution’s text,” he said, pointing to Article 1, Section 10, which says “No state shall, without the consent of Congress… engage in war, unless actually invaded, or in such imminent danger as will not admit of delay.”

“The Framers were very clear and precise” when it came to reining in the states, Yoo said. “Why not use the exact same language when it came to the president?” if they meant to likewise constrain him? The reason, he said, is that the “phrase ‘declare war’ never had the meaning it has now. No one talked about it as a check on the president’s ability.”

Instead, he argued that the primary way Congress has control over making war is via the purse. “Congress can cut off funds or refuse to fund any more operations,” he said.

Prakash agreed that “the purse can be used as a check on war making,” but said that ultimately, “only Congress can decide to declare war.”

Both Prakash and Yoo derided the Obama administration’s rationale for intervention in Libya in 2011 without congressional approval. Prakash called it “somewhat incoherent,” and Yoo said it was “utterly incorrect.”

In a 14-page memo, Caroline Krass, principal deputy assistant attorney general in the Justice Department Office of Legal Counsel, wrote that congressional approval was not constitutionally required because of “the limited means, objectives, and intended duration of the anticipated operations” in Libya.

Both Prakash and Yoo said the administration should pick a side—that congressional approval is required, or that it’s not. To argue that it’s only needed sometimes is, as Yoo put it, “legal acrobatics.”

To Yoo, it seems Congress doesn’t really even want the power to declare war. Rather, they’d prefer to “let the president take the initiative, and it if turns out badly, they can say ‘We never approved it.’”

On August 28, Speaker of the House John Boehner (R-Ohio) wrote to Obama asking him to “address on what basis any use of force would be legally justified and how the justification comports with the exclusive authority of Congressional authorization under Article 1 of the Constitution.”

Boehner continued, “It is essential that you provide a clear, unambiguous explanation of how military action—which is a means, not a policy—will secure U.S. objectives and how it fits into your overall policy.”

Contact Jenna Greene at jgreene@alm.com.