The Senate Judiciary Committee can approve or disapprove Judge Kavanaugh, but most of its members can't be reckless when they're doing it

Model Rule 8.2 of the Rules of Professional Conduct for lawyers, as recommended by the American Bar Association and adopted in some form by most of the states, reads:

 
Rule 8.2 Judicial And Legal Officials

(a) A lawyer shall not make a statement that the lawyer knows to be false or with reckless disregard as to its truth or falsity concerning the qualifications or integrity of a judge, adjudicatory officer or public legal officer, or of a candidate for election or appointment to judicial or legal office.

(b) A lawyer who is a candidate for judicial office shall comply with the applicable provisions of the Code of Judicial Conduct.

Several members of the Senate Judiciary Committee have made statements about Judge Kavanaugh's qualifications and integrity, ranging from the carefully measured to the wildly rhetorical.  Judge Kavanaugh is both a sitting judge and a candidate for appointment to judicial office.  Most of the committee members are lawyers and are subject to versions of Rule 8.2 in one jurisdiction or another, meaning that they are prohibited from making statements about Judge Kavanaugh's qualifications and integrity that they know to be false.  They're also prohibited from making a statement about his qualifications or integrity "with reckless disregard as to its truth or falsity."  It's an interesting legal point that the bar associations of several states might want to consider.