Meeting the requirement of proving good moral character as it relates to the practice of law is inherently difficult to those whose ideology depends from the propositions that the word of the Republican President supersedes any written law, and that the machinery of the law is intended to be used to facilitate the expansion and maintenance of the Permanent Republican Majority in all organs of the State.

People with actual morals tend to look dimly on both those propositions and those who act to carry them out.

And, FWIW, a pardon would be no help as to getting admitted to the Bar. Acceptance of a pardon – even for uncharged offenses – necessarily indicates an admission that, indeed, the recipient did commit crimes. The Bar can (and would) hold that against the applicant.

Maybe.

IF he had been disbarred or disciplined, there would be a public record of it. Simply, the Courts or Bar Associations that admit attorneys to the various state bars do their disciplining in public. (A note to the non-lawyers: it varies from state to state as to how attorneys are admitted to practice. In some states, licensing and admission are run by the state, usually through the state court system. In other states, licensing and admission is done by the State Bar Association, at core a private association with the public duty of licensing and admitting people. Those states are the so-called “mandatory bar association” states – you can’t practice without being a member of the bar association. In other states, it’s optional.)

IF a court had disciplined him, that discipline would be a matter of public record, as in a court order or opinion stating that (a) he’d been brought up on disciplinary grounds, (b) that he’d been ordered to show why he should not be disciplined, (c) that he’d been ordered disciplined and (d) the quantum of discipline. It would have been published in the official reports. Since I’m not a member of the bar in a mandatory bar association state, I cannot say how the news that he’d been disciplined would have been published, but suffice it to say it would be a public record.

More likely, IMHO, are one or both of two alternatives.
Alternative (1): self-disclosure. On his application to the DC Bar, he would have to have listed “pending” or possibly “threatened” litigation or investigations of him, regardless of whether they were administrative, civil, or criminal. One of the standard questions on the application is to the effect of “have you ever been a party in a civil, administrative or criminal action?” In other words, everything from “did you get sued over that car accident?” to “were you ever charged with anything that could conceivably bear jail time?” And, that includes all those things in juvenile court which they told you were “Sealed”. They weren’t.
If his answer was “yes” (and it is for almost anyone), then the follow up is “tell us all about it”.
I’d suspect the fact that the Congress hauled him in front of it and he won a TPM award for best performance in the field of testimonial stupidity, plus being the subject of innumerable blog posts and youtubes, got caught in this screen.

There are also provisions which require you to allow the bar authorities to have a look at your criminal record – including a waiver of letting them look at federal and state databases about you.

And then there is “have you ever had a security clearance?” and “if so, has it ever been revoked or limited?”

And “have you ever been fired from a job, forced to resign in lieu of being fired, or otherwise been compelled to give up some work?” followed by “please tell us all about it”

And, also, “tell us about every job you ever had and who you worked for, and allow us to talk to them”.

The application to a bar is even more intrusive than the application to work in the Obama administration.

Alternative (2): people complaining about you. This is where the idea that people writing letters may have had some effect, and I think this is what you were talking about.

There is no reason not to, and every reason to, write letters to the Bars which had admitted to practice the Bush crime family’s consiglieri – there is no telling when they may decide to get admitted somewhere else, and no telling when they might get into a bind in some other case where the bar authorities would take a look at the file and say “hey, ten thousand people complained about this guy – let’s make an example of him”.