Once upon a time...

... I was a counselor with the U.S. Army (... well, actually, I was a "Mental Hygiene Specialist", not a "counselor"). I worked as a drug & alcohol counselor in Korea for a year (2nd Infantry Division - the "Indian Head" folks - on the DMZ), in a "Mental Hygiene" clinic at Fort Bliss (while assigned to an M.P. unit - I also worked with prisoners in a stockade while they awaited either discharge or transfer to the re-training brigade at Ft. Leavenworth), and in a Basic Training unit, evaluating the psychological fitness of new recruits ("Yes, your recruiter lied to you!").

While at the Mental Hygiene clinic, I led "controlling your aggression" classes. The training was based on a wonderful little book whose title I've now forgotten... BUT - it included a very useful tactic: agree with your opponents. This simple tactic pretty much ends the argument.
You say I'm a far-left pinko commie?
You're right. I am.

This gives you breathing space to re-focus the discussion on issues, rather than responding to ad hominem attacks.

This is a tactic I'd like my favored politicians to adopt more often.
"You say I'm a tree-hugging left-wing pinko commie environmentalist?
You're right, I am!"
... "Now, can we discuss the issue of global warming and CO2 emissions?"

"You say I'm a socialist? Fine! You're right, I am!"
... "Now, can we discuss reforming health insurance?"

This was the basis of my brilliant advice to Speaker Pelosi.
"You say I'm complicit in torture and have accused the CIA of lying to Congress? You're right. I am and I did."
... "Now, can we discuss bringing the law-breakers among us to justice?"

It's a guerilla tactic. Don't stand up and get pummeled. Concede the point, and re-direct your efforts to the real issue.

Does this tactic work? Who knows? - No one seems to be taking my brilliant advice!