The first thing to say about Shami Chakrabarti's nomination for a peerage is that by any standards, and especially in comparison with many others who've received the honour, she merits it. I've long argued that Britain's second chamber should be elected, not appointed but, as the system stands, Chakrabarti is worthy of a place in the Lords. Her long service at Liberty and her expertise on human rights make her eminently qualified.

Sadly, that is not the prime way her nomination - as the sole name put forward by Labour leader Jeremy Corbyn, breaking his earlier promise to appoint no peers - has been judged. Inevitably, because it came only five weeks after she had delivered her report into antisemitism and other forms of racism within the Labour party, the two have been linked, with the assumption that both are compromised. The allegation is that she delivered a whitewash in return for those ermine robes. Or, as the Chief Rabbi, Ephraim Mirvis, tweeted, "the credibility of her report lies in tatters."

The truth is, her report's credibility was not looking too healthy even before we learned of her imminent elevation. That's not because of what's in it: as far as it goes, it's a sensitive, carefully written document. (Full disclosure: I was one of many people Chakrabarti spoke to as part of her work.) Its flaws lie in how it was framed, how it was launched and what it left out.

The framing is not wholly her fault. Perhaps she can't be blamed for those who skipped over her references to the "hateful or ignorant attitudes" and "occasionally toxic atmosphere" she'd found within Labour, preferring to seize instead on the report's first sentence - "The Labour Party is not overrun by antisemitism, Islamophobia or other forms of racism" - as if it were a total exoneration, as if "not overrun by" meant "has no problem at all with". But that opening line was curious. The accusation was never that every last person in the Labour party was an antisemite, but rather that there was a problem on part of the left that needed tackling.

More troubling was how she launched the report. Her inquiry was meant to be independent, yet she presented it with Corbyn at her side. When Sir John Chilcot delivered his conclusions on the Iraq war, he did not do a joint press conference with Tony Blair. Yet there stood Chakrabarti and Corbyn, examiner and examined, standing shoulder to shoulder.

The report's author then did a round of media interviews in which she acted not as Labour's invigilator but its defender. More troubling, she sat behind Corbyn as he faced the Home Affairs select committee, handing him helpful notes as he testified, like a lawyer advising her client.

So Chakrabarti didn't need to get a peerage for us to suspect she had crossed the line from judge to advocate. Indeed, one legal blogger makes a good case that she may well have agreed to become a Labour peer months before the issue of an antisemitism inquiry arose. That would mean she was compromised, but in a different way –- already beholden to Corbyn before she started.

Which points towards the ultimate problem. One way or another, Chakrabarti felt she had to write a report that would be embraced, rather than rejected, by the Labour leader - if only because she did not want her work to be in vain. That inhibited her from probing deeper into the strain of left thinking that the leader himself personifies and which so often collides with Jewish sensitivities.

So it was Corbyn who did nothing when, at the very launch of the Chakrabarti report, an activist abused Jewish MP Ruth Smeeth , alleging that she was part of a media conspiracy, prompting Smeeth to flee in tears. (Afterwards, Corbyn chatted warmly with the activist.) It was Corbyn whose statement at that launch included a sentence carefully worded to do just enough to liken Israel to Isis while allowing him to deny he meant any such thing. (You don't usually speak of "self-styled Islamic states" if you want to refer to Iran or Pakistan.) And Corbyn, whose record suggests a willingness to look past nakedly antisemitic statements so long as they are uttered by those he deems sound on Israel/Palestine. (Think of his defence of Rev Stephen Sizer, suspended for circulating the claim that 9/11 was an Israeli plot.)

Chakrabarti's report went nowhere near any of this stuff. She preferred to believe Labour's current leadership is part of the solution. She did not confront the grimmer possibility that it is part of the problem.

Jonathan Freedland is a columnist for the Guardian