Mr Blair is losing his authority just as he is gaining a new sense of boldness

The Prime Minister is behaving as if the doubts of others are merely confirming him in his own moral certainties

There have been two interesting recent developments in British politics, which are pulling in opposite directions. After nearly six years in office, Tony Blair believes that he has finally discovered how to be an effective Prime Minister. After doing what it was told for nearly six years, the Parliamentary Labour Party has rediscovered an interest in politics.

When Mr Blair declared that his Government was at its best when at its boldest, he was not only trying to inspire the troops. There was also an element of self-reproach. He now thinks that he should have been bolder earlier. To an extent, however, he is being unfair to himself, while also misdiagnosing the problem. The first Blair government did not always lack boldness. Incorporating the European Convention on Human Rights into British law, signing the EU Social Chapter, House of Lords reform: those were not trivial measures.

But they all had one thing in common. None of them had been thought through. As a result, the Government has no idea how to complete Lords reform, while Mr Blair complains that judges are restricting his freedom of action on asylum-seekers and that the eurozone will not reform its labour markets.

Yet these were not unpredictable consequences of the Blairite reforms. In each case, the Government was warned of the risks; in each case, it took no notice. So it is now stuck with the consequences of excessive boldness. That is what happens when you refuse to look before you leap.

In two other respects Mr Blair is right to reproach himself. From the outset he should have been much bolder on public services. At moments, he seemed ready to be convinced that only choice-driven and market-led reforms would work, but he always lacked the final impetus of courage. That was also true on the euro. For euro-sceptics, the summer and autumn of 1997 was the hour of maximum danger. If Mr Blair had been prepared to throw all his authority into a campaign to abolish the pound, he might have succeeded.

Yet one can understand why he hesitated. Both the euro and the public services are difficult, controversial questions. It is not as if there was a businessman waiting at the back door of Number 10 with a blueprint for NHS reforms. Radical public service reform would have involved a long, hard slog, with public expectations raised long before any improvements in performance, while there would also have been trouble with the trade unions – and the Labour Party.

As for the euro, there is no certainty that Mr Blair would have won a referendum, even in 1997; after all, he only just carried Welsh devolution. Nor would public disquiet have been stilled by a narrow win, the most he could have realistically expected. If Mr Blair had been bolder on the euro and on public services, he would have been steering his plane straight for the storm clouds. He would almost certainly have had a much smaller majority at the last election.

This highlights a basic difference between Mr Blair and Lady Thatcher. Mr Blair can never decide whether he is her heir, or the man who liberated the country from 18 years of Thatcherite captivity. But when it comes to popularity, he is no Thatcherite. She regarded popularity as capital to be invested and expended. Indeed, she was happy to run a deficit; between elections, her account at the bank of popularity was usually overdrawn. In contrast, Mr Blair has been a miser of popularity, never happier than when sitting in his big tent counting his gold, desperate to ensure that not a single coin escapes.

He now assures us that this will change, and he cites the forthcoming war as evidence. He has a point for, on Iraq, he is in conflict with public opinion as well as his party. The big tent has been dismantled and folded away. Yet the PM is behaving as if the doubts of others are merely confirming him in his own moral certainties. But there is a difficulty, which he may not fully understand. Back in 1997, a large number of voters believed in him, while a large number of Labour MPs were awestruck. I remember a description of encounters between junior ministers and the PM in those early days, a description from an older and cynical minister. His colleagues would emerge from the PM's study with a strange light in their eyes, as if they were walking on air, repeating Blairite slogans, as if in a mantra. What they said never made much sense, but it was hard to fault as a loyalty-bonding exercise.

That sort of magic no longer works. Instead, a lot of Labour MPs have remembered that they did not come into politics to let market forces loose in the health service and George Bush loose in Iraq. They are still not ready to overthrow Mr Blair, but it is no longer inconceivable that they should do so. A year ago, who would have thought that the most secure party leader would be Charles Kennedy, the man who took the weight out of lightweight.

Equally, a large number of voters no longer buy the Prime Minister's act. Excessive spin and insufficient performance have bred disillusion. They, too, are not ready to sack him, but these days, when he preaches, they laugh.

Some of Number 10's advisers believe that this will all change after a successful war, and it is easy to construct a Blair-boosting scenario. This would involve a quick military win, with a minimum of casualties and a maximum of Iraqi defections, accompanied by the hard evidence of hideous weapons – but not used on allied forces. Mr Blair could then fly in, looking sombre in front of the weapons sites and covered in smiles as delighted Iraqi children festoon him with garlands: the mother of all photo opportunities.

This could happen, but even if it did, there might be no great impact on public opinion. A lot of voters could respond along the lines of: "OK, you were not as wrong about Iraq as we feared, but when are you going to do something about schools/ hospitals/crime/transport? Stop crowing and get on with it.''

That deals with the rosy outcome. But what if Saddam still has a few thousand loyal troops? Instead of sending them into suicidal combat with allied air power and armour, he might choose to scatter them in penny packets to hold towns and villages, while keeping a good force for Baghdad itself.

If so, there could be unpleasant outcomes. It is never easy for an army to fight its way into urban areas; in that type of warfare, smart weapons lose their advantages. It would, of course, be possible simply to besiege Baghdad, but that would mean terrible sufferings for the civilians.

We can only hope that Saddam's powers disintegrate with the imminence of defeat, and that the Baghdadis of 2003 do not behave like the Berliners of 1945. But a messy, protracted endgame would create problems for Mr Blair, especially if there is only ambiguous evidence on weapons of mass destruction – especially if the war began without a second UN resolution.

War is unpredictable. A lot will depend on luck. Mr Blair may be buoyed up by self-belief and self-righteousness, but this will not necessarily endear him to the public mood. For the first time during his premiership, Mr Blair has put himself at the mercy of events.