Las Vegas (CNN) -- National security, the fight against ISIS and the role of Muslims in American society immediately dominated Tuesday's Republican presidential debate -- the first since terror attacks shook Paris and San Bernardino, California. Four lower-polling GOP White House hopefuls kicked off CNN's so-called "undercard" debate by raising alarm about the threat of radical Islam. And many of them slammed the proposal from Donald Trump, the party's front-runner, to temporarily ban all Muslims from entering the United States. "You may think this makes us safe, but it doesn't," said South Carolina Sen. Lindsey Graham, one of Trump's most vocal critics. "Donald Trump has done the one single thing you cannot do -- declare war on Islam itself"/CNN. More here.

DFO: Feel free to post your thoughts re: tonight's Republican debate?