Former Sen. Joe Lieberman (D-Conn.) said that he was “shocked and disappointed" by President Obama's decision to seek approval for military action in Syria from Congress.

At the same time, Lieberman urged his former colleagues to approve the use of force, arguing that doing nothing would be the worst result.

Lieberman on Fox News Sunday said that a congressional vote against the use of military force would be “catastrophic.”

“Notwithstanding what I said a few moments ago about how shocked and disappointed I was by the president's decision yesterday to go to Congress for authorization — because I think he has the authority now to do that and that's exactly what the commander in chief is supposed to do — the worst of all ends to this whole saga would be for Congress not to give the president authority to act,” he said. “It would be catastrophic.”

He warned that those lawmakers looking to “hang the president out there” with a no-vote would instead be “hanging America out there.”

“They're going to be hanging America out there, compromising our credibility in the world. So I appeal to my fellow members of Congress to give the president the authority that he's asked for now,” he said.

Lieberman said he'd lobby his former colleagues to approve the use of military force, and said he'd particularly work to convince Sens. Lindsey GrahamLindsey Olin GrahamDems aim to turn ObamaCare hikes into election weapon Steyer brings his push to impeach Trump to town halls across the nation Trump formally sends Pompeo nomination to Senate MORE (R-S.C.) and John McCainJohn Sidney McCainZuckerberg: Maybe tech should face some regulations Schiff mocks Trump: Obama, Bush didn't need staff warning 'do not congratulate' Putin GOP senator tears into Trump for congratulating Putin MORE (R-Ariz.), both of whom have expressed reluctance to back a limited military attack, which they have criticized as ultimately ineffective.