With his talk of "matching the Tories" in the latest opinion polls, you would think that his party was on the brink of sweeping to power.
Granted, polls can be notoriously inaccurate, but even to be running neck and neck with Theresa May's Conservatives (some polls have Labour trailing way behind) should be a cause of great embarrassment.
Ian Austin quits Labour: Huge reaction to MP's resignation from party
At pretty much any other time during the modern era, a Labour Party in opposition to a government in such disarray would be 20 points clear and disappearing over the horizon.
It would be a matter of when, not if, the party's leader took office.
However, as the events of the last five days have shown in glorious technicolor, Jeremy Corbyn is a specialist in shooting himself in the foot.
On the very day that seven MPs quit, citing Brexit and the party's failure to tackle anti-Semitism, Labour's ruling committee was busy readmitting the divisive figure of Derek Hatton.
Unsurprisingly, it took Old Militant Degsy only two days to pick up a suspension, after a 2012 tweet emerged in which he blamed Jews for Israeli government policy.
WATCH: Ian Austin MP latest to quit Labour
Meanwhile, Mr Corbyn wants those who have left – which now number nine after Ian Austin decided enough was enough – to resign as MPs and fight byelections.
Absolutely no attempt has been made to speak to any of them, to address their concerns and change the way his party operates.
How sad that the Labour Party in its current form is more concerned about pandering to a washed up old Trot than reaching out to its own MPs.
Messrs Corbyn and McDonnell have been the twin ringmasters behind Labour's collapse into a circus.
They shout up the party's 'progressive' policies, claiming they will end poverty and spearhead economic reform, refuel the NHS and provide high quality education for all.
Yet when MPs who have devoted their lives to bringing about positive change decide it's time to go, they act as if they don't have a care in the world.
Tom Watson, a lifelong Labour man, has called for urgent change at the top of the party. More than most, the West Bromwich East MP can see how dispirited many of the party's MPs have become.
He will know that a Labour Party that is glued to a hard left ideology has no chance of success at the ballot box.
But despite a few warm words from Mr McDonnell, the likelihood is that his pleas will fall on deaf ears.
It appears that as Mr Austin says in today's Star, Labour has now left the mainstream behind, possibly for good.
It is likely that Mr Corbyn does not care how this all looks to those who live outside his hard left cabal.
As long as his confused followers keep on banging the Corbyn drum, then everything will be rosy in his north London allotment.
Labour members who have bought into the Corbynite way will keep explaining away his many failings.
They will criticise attacks against him, branding them unjust and fuelled by a lack of understanding.
But to millions of moderate Labour voters that no longer recognise their party, this new form of politics is nothing short of an affront.
The loony left has well and truly returned.