To say that a politician has made a decision on political grounds is a statement of the obvious. All ministers' decisions are political. But some are more political than others.
If you want a reliable guide to how much politics is involved, use two tests. First, is the decision heavily leaked in advance? This is a certain sign that ministers want the newspapers to report the document in a particular way. They want to establish their own narrative about what is going on, and to marginalise criticisms of the document that may emerge once other people have the chance to read it. By advance leaking - or briefing as they prefer to call it - ministers put everybody else on the defensive, making them appear malcontents or whingers.
The second test is whether the leaks go to members of the Westminster lobby - the political correspondents - or to specialist reporters, such as education correspondents. The latter will understand the background and, therefore, ask the more searching questions about the subject involved, whether it be education, health or whatever. The political journalists, naturally enough, understand the politics. Will it cause a backbench revolt? Will it put the Tories on the back foot? Will it delight "the middle-classes", who are perceived in the Westminster village as an amorphous, undifferentiated mass, whom it is best to keep on-side, rather like the Shias in Iraq?
Political correspondents, who leave central London only for party conferences, know little - beyond what a minister chooses to tell them - about the effects of a government decision on Burnley pensioners or Barnsley teenagers. Indeed, their reports are often so dominated by contrived political drama that it becomes difficult to know what the decision is actually about.
Apply our two tests to Ruth Kelly's white paper on 14-19 education and we must conclude that it fell into the "highly political" category. Its main points were widely trailed in advance, particularly on the Sunday before it was published the following Wednesday. All the Sunday stories were written by political correspondents. All portrayed Ms Kelly as bravely "defending" A-levels or "insisting" on harder maths and English exams.
Poor Sir Mike Tomlinson, who had chaired an inquiry that proposed a single diploma system for 14 to 19-year-olds and the end of A-levels and GCSEs, was just a man threatening a "backlash", to use the Sunday Times expression.
The writers will have understood little of the pressures that have built up in schools and colleges over more than 30 years, persuading almost everybody who works in education that A-levels should be abolished, the number of exams reduced and the academic and vocational streams united.
In a previous TES column (October 29, 2004), I asked why ministers had set up a pound;1 million, 18-month inquiry when they should have known that it would recommend an end to A-levels. Now I wonder if Sir Mike was set up from the start so that ministers could be seen riding to the rescue of A-levels on the eve of a general election.
This sorry episode illustrates everything that is wrong with our political culture. I do not expect ministers to accept the results of an inquiry without question. They had every right, indeed a duty, to canvass opinion and to have the proposals properly aired and critically debated. They did nothing of the sort. Downing Street decided that A-levels must stay, and brushed all dissent aside.
The ayatollahs of the English middle-classes - the editors of the Daily Mail - are thrilled. Labour has probably retained a few thousand votes which it might otherwise have lost.
But I suspect that almost everybody involved with 14-19 education will now be a little more disillusioned with politics in general, and new Labour in particular, than they were a few months ago.
Peter Wilby is editor of the New Statesman