Joseph,
any attorney that makes knowingly false claims in court just be reported to the Bar Committee (different name in each state) and have his/her license suspended/revoked. Lawyers are not allowed to make knowingly false claims or allow their clients to testify falsely (if the lawyer knows the testimony is false).
I practice family law. I have never knowingly made a false claim in court. This is not to say I have never made a statement based on information from a client that has been legitimately refuted. I did not know it was false.
For example, if a husband says he earns only $1000 week (and shows me pay stubs to match) and I argue based on that he can afford only X dollars per week child support or alimony and the wife’s attorney presents evidence gathered by their investigators that the husband also has a side job earning $400 week cash, then my claim has been refuted, but I didn’t knowingly present a falsehood.
I had a client last year who showed me pay stubs showing $75,000 yearly income. I refused to submit his signed financial affidavit to the court. I knew that he could not maintain his lifestyle on 3 times that amount and I would not suborn perjury.
Criminal attorneys are taught to never ask the client if he/she is guilty. This is knowledge better not known by the attorney in order to mount an effective defense.