Tim Kaine actually said...
I believe the President was right to seek an approval. And while I am disappointed that our body as a whole did not ultimately act, that authorization, which the President took to the G20 summit at that time in Russia, gave him a credible threat of the potential use of force to convince Putin that he needed to have Assad give up his chemical weapons.
Context
Kaine supports Obama's request for congressional approval regarding military action in Syria.
12/12/2017