By Nick Assinder
Political Correspondent, BBC News website
If Wednesday started badly for the prime minister with the loss of another cabinet minister, it ended on an even worse note.
While most in Westminster had been transfixed by the drama surrounding David Blunkett's departure, a potentially far more damaging scene was being acted out in the Commons as the prime minister's flagship anti-terror laws were being torn to pieces.
Blunkett affair was damaging the prime minister
First, his large majority was slashed to just one and then his Home Secretary was forced to withdraw proposals for 90 day detention to stop them being defeated by MPs.
The thing that unites these events is that they were both pretty inevitable and, many Labour MPs now argue, preventable by any prime minister who retained full authority and a sure touch.
The fact that Tony Blair failed to prevent them has only served to fan the flames surrounding his own position - already seen as weakened in the wake of cabinet revolts, splits and near open warfare.
So Mr Blair faced his cabinet on Thursday morning once again having to urge his team to focus on the big picture - notably securing his so-called legacy reforms.
He tried to stiffen their spines by admitting things were tough because he was doing the right thing on welfare reform, terrorism, public servcies and so on. But he gave no sign he believed things were tough for his own leadership.
It all started when Mr Blunkett left the Cabinet for the second time in a year declaring he did it for the good of the government and Tony Blair's premiership.
His simple "mistake" of breaking the ministerial code was proving a massive distraction from the real business of government and was embarrassing the prime minister, he declared.
Clarke was forced to climb down
He had done nothing wrong and there had been any number of lies and innuendoes spread about his business and private life.
In a charged press conference he gave the impression of a man who, under other circumstances, would have continued to fight his corner against his enemies, who he suggested were as much in the media as on the Tory benches.
But it was the prime minister people really wanted to target, he said, and he clearly wasn't about to help them by staying.
He was certainly right about that, and the damage his continuing presence in the cabinet was doing to Tony Blair.
And whether he decided to quit after a long and interrupted heart-to-heart with the prime minister on Wednesday morning, or whether he was sacked as some suspect, there will still be questions over how serious and lasting that damage has been.
The prime minister's continuing support for his friend and ally had worried many on the Labour benches who believed Mr Blunkett had lost his bearings and become dangerously accident prone and unable to see the problems caused by his own actions.
The longer the prime minister stuck to him, the more the prime minister would be attacked for losing his own judgement, and authority, they feared.
Blair was reluctant to lose his friend
And so it was when, just an hour after Mr Blunkett's resignation was officially announced, Mr Blair was under personal attack from Michael Howard on precisely those grounds.
Only hours later, there was what many saw as a prime example of that waning authority as Labour MPs humiliated the government over its anti-terror laws.
So, while Mr Blunkett's resignation may have been another personal tragedy for him, it has helped push the prime minister closer towards what many fear may become a genuine crisis of leadership.
In just a few days, Mr Blair has seen some of his Cabinet in open revolt over his education reforms, a major ministerial split over a smoking ban, continued rumblings against his wider welfare reforms and speculation over his allegedly dwindling authority.
Draw a line
The fact Mr Blair had defiantly brought Mr Blunkett back into the Cabinet only five months after he was sacked for the row surrounding the fast tracking of his nanny's visa had already raised questions over his judgement.
Many pointed to the similarities between Mr Blunkett's departures and those of Mr Blair's other great friend Peter Mandelson, who twice had his career revived after resignations.
The prime minister needed and trusted Mr Blunkett to push through his keynote reforms of the welfare state.
And he showed great loyalty to him over both episodes which led to Mr Blunkett's resignations - a trait some feared would damage him.
The fact this all happened at the time the prime minister was already under pressure, with many on his own side said to be looking beyond the end of his premiership, added to the worries.
So, while Mr Blunkett draws a line under his cabinet career, Tony Blair might find it more difficult to draw a line under his own troubles.