By Mike Baker
BBC education correspondent
"We will improve school discipline". Cue thunderous applause.
How many times have we heard this during education debates at party political conferences?
This week the Conservative leader, Michael Howard, highlighted school discipline as an educational priority.
He told the Conservative Party conference that on "Day One" of a Conservative government he would "start to give head teachers control over their classrooms".
Promising better discipline is clearly popular with the party faithful. It probably goes down well with voters too.
But just how much influence do politicians really have over school discipline?
Of course, politicians can introduce laws that, at least in theory, may impact on school discipline.
This was what all those debates about caning were about after corporal punishment was abolished in state schools in 1986.
For many years after that, calls for the restoration of corporal punishment were guaranteed to go down well at Conservative Party conferences.
Indeed, in the last months of John Major's Conservative government, Tory backbenchers voted in Parliament to restore it.
It was a popular move on the Tory side but it was defeated because Mr Major imposed the parliamentary "whip" (no pun intended) on Conservative ministers, requiring them to vote against restoration.
Nevertheless nearly 100 Conservative MPs supported the cane. Even the then Education Secretary, Gillian Shephard, said her personal view was that the threat of the cane could be a useful deterrent to bad behaviour.
It is a sign of changing times that Michael Howard did not, this week, feel able to promise the return of corporal punishment.
Parents can appeal against their children being excluded
So, with the cane now apparently off limits, what can politicians do which would actually make a difference to classroom behaviour?
The last Labour manifesto promised to "ensure that head teachers have the powers they need to tackle disruption and unacceptable behaviour". But no details were given.
Labour has good reason to be cautious about making big promises on school discipline. In 1997, the newly-elected Labour government promised to reduce permanent exclusions by one-third.
But it soon emerged that cutting the number of school expulsions was not necessarily the same thing as reducing bad behaviour.
Indeed teachers complained that it made discipline worse as schools came under pressure to keep disruptive pupils in the classroom.
The number of excluded pupils did fall quite dramatically and the target was met early. But under pressure from the teacher unions, Labour dropped the target in 2001 and the number of exclusions subsequently crept up again.
More recently, the last Education Secretary, Estelle Morris, got into some bother when she criticised a local authority Appeals Panel which had reinstated two pupils excluded for threatening a teacher.
Despite some tough talking, it soon emerged she had no powers to do anything about it. Indeed, despite later promises to make it harder for Appeals Panels to reinstate pupils, the latest guidelines still allow this to happen.
Indeed it is hard to see how they could not. After all it would not be much of an appeals process if exclusions could not be overturned.
For all their genuine desire to tackle school discipline, politicians lack the means to do anything about it
So, in view of Labour's difficulties over school discipline, what changes would the Tories introduce to give head teachers control over the classroom again?
National targets for exclusions are not a possibility, since the Tories are opposed to central interference in the running of schools.
So their proposals seem to boil down to one change: abolition of Appeals Panels.
These panels are the only body to which parents can appeal if their child is expelled. But how often do they actually reinstate pupils?
In the most recent year for which there are figures, there was one appeal for every nine expulsions.
Of these, just one in five went against the school. In all, the number of cases where a pupil was ordered to be reinstated was 149.
So, that is just 149 cases out of over 9,000 exclusions in the year.
So, whatever the rights and wrongs of abolishing Appeals Panels (and one could foresee a challenge in the courts if all right of appeal was removed), it would only mean the removal of around 150 difficult pupils from their classrooms.
It might, of course, be argued that this is as much about perception as about reality. Perhaps if parents knew that exclusion meant exclusion, with no arguments, perhaps it would have an effect on behaviour. Who knows?
But it does underline the reality that, for all their genuine desire to tackle school discipline, politicians lack the means to do anything about it.
And if politicians mean it when they say they do not want to promise what they cannot deliver, then perhaps they should be cautious about their claims to improve classroom discipline.
This is not to underestimate the importance of establishing good order in schools. We know it affects other pupils and that it is one of the main reasons cited by teachers for wanting to leave the profession.
As Ofsted will report this week, the challenge of coping with pupils with behavioural problems is not easy for many schools.
But just because there is a big problem out there does not mean there are any easy answers.