"Very damaging", was the conclusion of one of Labor's most senior and respected figures after monitoring the commission hearings.
Shorten's shifty performance under cross-examination on relations between unions and employers exposed the Labor dilemma for all to see.
Put simply, the question is whether an already compromised William Richard Shorten – Shorten was disloyal to two Labor leaders, Kevin Rudd and Julia Gillard – is electable under any reasonable scenario, including widespread disaffection with Tony Abbott.
And, more immediately, whether Shorten, given that he is damaged goods, will have the authority to assert himself over Labor's national conference at the end of this month at a time when his own right faction is yielding ground to the left?
Nothing that happened before the royal commission will have lessened a public perception of Shorten's untrustworthiness – or rendered him more electable, or knowable.
Among criticisms – fair or not – is that the Opposition Leader does not stand for anything beyond his own advancement.
Labor insiders could not help contrasting Shorten's meandering performance this week with a crisp appearance by Gillard before the royal commission in which she dealt relatively effectively with embarrassing personal questions about her relationship with a former AWU official.
"When I was a lawyer I never had a client on a witness stand as bad as him," is the judgement of one Labor insider.
If that's the best Labor's got I'd hate to see the rest.