The first blows on Corbyn may come from the left
Jeremy Corbyn's most vulnerable flank is on his Left not the Right. Massed against him on one side are the ranks of MPs who opposed a winner isolated in a tiny minority in his own Shadow Cabinet, frontbenchers contradicting their leader at will after reluctantly joining his team.
Citizen Corbyn, elected with more votes than the Tories have members as he's fond of warning sceptics, will parade his grassroots legitimacy at Labour's conference in Brighton next week where he's guaranteed a hero's welcome from the army of activists who feel this time they've really got their party back.
But he's like a trade union general secretary elected by the workers who faces a hostile executive or a company chairman constantly battling directors on the boardroom despite a mandate for reform from shareholders. Something must give.
Corbyn's strength on the Left is also a potential weakness because it isn't going to be easy for the unlikely leader to sustain the movement that swept him to victory when the principles which make him so exciting as a politician are contradictory.
He's admired for sticking to his guns, adopting principled positions including scrapping Trident. He also champions the principle of Labour's conference deciding party policy, the democratic principle a leader prepared to be led. He may not enjoy some of the directions the party heads.
Trident could prove the weapon of mass destruction that blows apart the Left alliance within a fortnight of the most stunning of leadership results.
It was put to me thus by a Labour loyalist desperate to keep the show on the road after a bumpy start.
Should the conference debate the £100-billion Doomsday weapon and vote to abandon it, the whispers are Maria Eagle (Defence) and Vernon Coaker (Northern Ireland) could be the first Shadow Cabinet resignations. Equally or perhaps more dangerously for Corbyn, he'd be on the wrong side of a Unite union which backed him to the hilt and serves as a Praetorian guard but is unlikely to sit back quietly if the jobs – and union subs – of the thousands of well-paid skilled workers it represents went down the Swanee with Trident.
Should the conference vote to retain Trident, idealistic Ban the Bombers who gave the Corbyn bandwagon an enthusiastic push would be instantly disillusioned and the veteran unilateralist leader himself would be strapped into a nuclear policy he's publicly opposed for virtually all of his life. The CNDer who vowed to accept conference policy would find it humiliating, indeed impossible, to walk into the Aye lobby of the House of Commons alongside braying Tory MPs to endorse Trident.
In politics it's known as a lose-lose nightmare. Delaying the question until next year or the one after would buy time until an eventual crunch when, whether Labour's for or against Trident, part of his base is going to revolt.
And if his Left flank's weakened, enthusiasm wanes or, worse still, deadly screams of betrayal are heard, that's when opponents on Corbyn's Right will strike.
Corbyn's office is strengthening its political network as well as the spin operation, spotting the perilous traps ahead including Trident. They'll have their work cut out. Winning the leadership may prove to have been the easy bit.
Kevin Maguire is associate editor (politics) of the Daily Mirror