Let me guess. Your co-worker believes in 'Big Government"? Suddenly 'Big Government' is bad? Yet he continues to support and vote for politicians who want even "Bigger Government'?
He deserves to be challanged on that point. Yeah, I know, in an office setting YOU and't allowed to do that, only his attacks are allowed.
And I wouldn't waste my time with her. She's too far gone. Most of the people in the office just shake their heads and go back to work.