"Yes, any nutjob with a mandate of one and a bomb in his backpack *can* seek to hold fellow nutjobs like Tony Blair accountable by blowing up innocent bystanders, no matter how unfair this may be. Rather than wailing about the injustice of it all, Brits should just take practical steps to reduce the chances of this happening -- by withdrawing all their troops from Iraq and binding over Blair for trial as a war criminal."
First, Carl's advice is superfluous. Britons have done a lot more to constrain their government's policy in Iraq than Americans have. British MPs did table a motion to impeach the Prime Minister. Ordinary Britons have made their opposition to the war felt in a way that was largely absent in the US.
Second, the reason to oppose the war is because it harms Iraqis, not because it harms Britons (it doesn't). Solidarity with the Iraqi people is a positive force that can stop Blair. Fear of terrorism will only accelerate attacks on civil liberties, and the persecution of Muslim populations here.
Third, nobody in Britain has been killed because of the Iraq war. As far as we can see they have been killed because they are unbelievers (see testimony in the Bouyeri trial for a comparison).
Finally, it would be wrong to change policy because it might provoke some head case to plant a bomb. If that were the right solution then Britain ought to outlaw homosexuality (to avoid right-wingers bombing Soho) and America ought to withdraw from the UN (to stop a follow-up to Timothy McVeigh) and all technological progress should cease to stop a copycat Unabomber.