By Martha Kearney
Presenter, BBC Radio 4's The World at One
It is a good rule for political leaders.
Lady Thatcher understands the power of symbolism
If you commission a report, be pretty sure that you will like the outcome.
This week George Bush got what he wanted, a protégé of Gordon Brown came back to bite him and David Cameron's greenery is making his grassroots bristle.
On Monday, General David Petraeus and Ambassador Ryan Crocker reported to Congress on the US surge strategy in Iraq.
This has been a highly risky venture for President Bush given domestic feelings over the war but the General reported success especially in Anbar province where local sheikhs are co-operating with US forces against Al Qaeda.
Many Democrats claimed that Petraeus had been unduly influenced by the White House but interestingly the Brookings Institution (not normally aligned with the administration) which carried out its own survey in July also concluded that the surge had been working.
The justification for the surge was to create a safer environment for political agreement and stability to be achieved.
That certainly hasn't been the case - but President Bush has been able to use the report as justification for leaving the majority of troops in place with only gradual withdrawal and no timetable as the Democrats wanted.
In a not dissimilar exercise, Gordon Brown commissioned a report back in 2001.
He knew that taxes would have to go up to pay for huge new investment in the NHS so he got the former chief executive of the NatWest bank, Sir Derek Wanless, to write a report on the NHS's problems.
His conclusions justified the extra spending.
Sir Derek's report for the King's Fund this week was rather less helpful as it pointed out that some of the new money had been wasted - spent on pay without achieving more productivity.
This is potentially very difficult for Labour as opinion polls show that voters trust the Conservatives more on health.
Policy reports have been a mixed blessing for David Cameron.
Originally devised by Oliver Letwin, the idea was to show new priorities for the party, to bring in outsiders like Bob Geldof and to generate new ideas.
The coverage for the Quality of Life Policy Group was cleverly handled, spread out through the course of the week and the proposals won plaudits from Greenpeace and Friends of the Earth.
But some of the ideas were controversial, like local authorities having the power to insist that out of town supermarkets levy a carparking charge, green taxes and a moratorium on airport expansion.
Some Tories fear Mr Cameron has his head in the clouds
Those proposals are unpopular with many Conservative activists and MPs who say privately they are unConservative and show that old Etonians like David Cameron and Zac Goldsmith are out of touch with ordinary people.
Even if the Conservative leader rejects the most controversial ideas, the risk is that voters will still believe they are Tory ideas as they got so much coverage.
But David Cameron must be pleased that his party is finally getting some political momentum after a terrible summer and there are signs that not all is well with Labour.
Gordon Brown's political strength rests on his appeal as a strong and competent leader.
The return of foot and mouth disease this week could damage that reputation.
It was the prime minister, after all, who took personal control of the crisis during the last outbreak.
The Conservatives have suggested that the Chief Vet was put under political pressure to lift restrictions too early.
That is unproven but any sign that DEFRA failed to act properly - like failing to close footpaths early enough - is bound to rebound on Number Ten too.
So where does all this leave election timing?
Certainly Westminster is abuzz with speculation.
One Tory MP I bumped into said that they were remaining publicly loyal to David Cameron for fear of causing trouble before an October election.
He said he didn't really think Brown would call one but "he'd be mad not to".
I wonder if that topic came up over tea (black for Lady T) in the Downing Street flat this week.
What an intriguing invitation.
Tony Blair, while professing his admiration for Margaret Thatcher, certainly didn't pose for a photograph with her.
But times have changed.
There is certainly a reassessment going on about her achievements and perhaps a certain nostalgia too.
I recently saw her face on a T shirt in French Connection.
Gordon Brown, as well as wrapping himself in the "conviction flag", is colonising ground left vacant by David Cameron who has been distancing himself from the Thatcher legacy as part of the party's repositioning.
The lady herself certainly knows the power of symbolism.
Surely no coincidence that she was wearing a dress that if not quite red, was certainly close enough for New Labour tastes?
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