WASHINGTON — When Brett M. Kavanaugh was preparing for his second confirmation hearing for a seat on a federal appeals court in 2006, he got some unwelcome news. The American Bar Association, which had earlier given him its highest rating, had reconsidered.

The revised rating, the group explained, was prompted by new concerns about Mr. Kavanaugh’s demeanor and veracity, foreshadowing some critiques of his testimony last week before the Senate Judiciary Committee in response to accusations of sexual misconduct.

The bar association’s new rating in 2006 — “qualified” instead of “well qualified” — was still quite positive. It meant, the committee explained, that Mr. Kavanaugh had met its “very high standards with respect to integrity, professional competence and judicial temperament.”

The revised rating was a minor blemish on a glittering résumé, and it was discounted by conservatives who viewed the bar association as a liberal interest group. The group’s concerns did not prevent Mr. Kavanaugh from being confirmed that year to the United States Court of Appeals to the District of Columbia Circuit. And when he was nominated for the Supreme Court this summer, the bar association unanimously rated him “well qualified,” although Robert M. Carlson, the association’s president, called last week for “a thorough F.B.I. investigation” before a Senate vote.