Some at Westminster are describing it as Tony Blair's "hard cop, soft cop reshuffle".
Pugnacious John Reid is widely seen as a hardline machine politician - with his Communist Party background, he received early training - and will be the prime minister's hard man in the House during the stormy times ahead.
John Reid and Ian McCartney leave No 10 with their new jobs
Of those there will be a few, including the gathering rebellion over foundation hospitals.
New party chairman Ian McCartney, though by no stretch of the imagination a shrinking violet, is viewed warmly by Labour's affiliated trade unions.
That could prove extremely useful indeed for Mr Blair right now.
Labour's cash crisis means it desperately needs to reach a new funding deal with the unions. Mr McCartney is better placed than Dr Reid to coax the necessary donations from them.
Cook's modernisation over
If there had been any doubt about it, Dr Reid's appointment also signals an end to the constitutional and parliamentary modernisation agenda that Robin Cook pursued in the job.
Mr Cook supported proportional representation, strongly believed in constitutional reform and changed the working hours of the Commons.
He made no secret of his disagreement with Mr Blair's U-turn on a more democratic House of Lords, and found his bid to give select committees more independence thwarted by government whips.
Aside from the reform of Commons hours, none of these approaches sat easily with the prime minister's position on the same issues. Dr Reid will be a leader of the House who makes Mr Blair's life easier.
Remember too that Mr Cook, the most dangerous debater in Parliament, is now on the backbenches himself.
If opposition were to coalesce around him, this could prove lethal to any deeply unpopular piece of legislation.
Allied with Chief Whip Hilary Armstrong, Dr Reid will now make up one half of a formidable strong-arm duo facing a Parliamentary Labour Party which just recently gave Mr Blair a record-size revolt.
Labour's funding crisis
Mr McCartney is well-suited to the selling job he will have to undertake as party chairman.
He must sell the party's policies to its members, but also to the unions Labour needs to bankroll its record overdraft.
As trade and industry minister in the government's early days, he battled mightily on the unions' behalf as his then boss Stephen Byers sought to trim legislation bringing in the national minimum wage.
He is steeped in union tradition, a politician who describes himself in Who's Who as "of proud, working-class stock".
His appointment is also notable because his relations with the party's general secretary, David Triesman, are known to be uneasy to say the least.
Negotiations between Mr Triesman and Labour's main union donors have been going on since last year to secure a long-term funding deal which would help stabilise the party's financial position.
The talks have yet to reach agreement. The hope must be that adding Mr McCartney to the equation will hasten a deal, never mind any difficulty between the general secretary who will have to work closely with him.
But all of this, of course, is just the appetiser before a far greater reshuffle expected after Easter.
Friday's changes were born of necessity following ministerial resignations over Iraq.
Once the war that sparked those is over, Mr Blair will set about a far more extensive rearrangement, with a view to shaping his government to fit the fight for the next general election.