Since Chuka Umunna is out of Labour’s leadership contest, he’s also off George Osborne’s list.  This will be a relief to Umunna, if he has any sense about him.

The Chancellor’s camp believes that the Conservatives “defined” Ed Miliband early – and that, once this had happened, the odds of him breaking through with voters were lengthened.

This may be right and may be not but, undoubtedly, Downing Street, the Treasury and CCHQ turned a tool against Miliband that they pinched from his patron, Gordon Brown – the dividing line.

The former Chancellor drew so many at Westminster that the very grass of College Green was thick with chalk.  His best-known was the Spending Trap (or; will the Tories match our spending plans?)

If the Shadow Chancellor promised to do so, the political centre of gravity would be dragged to the Left – and the Conservative Right would agitate.

And if the Shadow Chancellor didn’t, Brown would swoop – and declare theatrically than the next election would represent “Investment v Cuts”.

The device worked well enough for Brown until the economy collapsed and, with it, his credibility.  Which brought Osborne into the Treasury, and allowed him to turn the tables.

In place of Brown’s Spending Trap came the Debt Trap and the Welfare Trap.  Will Miliband commit to our plan to reduce debt?  Will he sign up to our proposals for benefits uprating?

The trap’s pit, if you like, would be a Commons vote (on a Charter for Budget Responsibility or a Benefits Uprating Bill).

If Labour’s front bench signed up to these, the party’s MPs would have to troop through the lobbies in support.  The traps thus stretched Labour by stoking rebellion.

Andy Burnham, Yvette Cooper, Liz Kendall, Mary Creagh: Labour’s leadership contest entrants must prepare themselves now for new traps – as Osborne, like Brown, exploits the vantage of government.

The Conservative Manifesto committed a Tory Government to a lower benefits cap and an eventual budget surplus.  It’s not hard to imagine what follows next.

Will Labour’s new leader sign up to our new benefits cap?  Will Labour’s new leader commit to our budget surplus?

If he – or she – doesn’t, the new leader will be framed by Osborne and Company as “soft on welfare” and “weak on the economy”.

But if he does, the discipline of Labour’s Parliamentary Party will be tested, at a time when its wipeout in Scotland has left it very fragile indeed.

And the political centre of gravity in Britain will be moved to the Right.  Osborne is turning Brown’s weapon against Brown’s party with a vengeance.