Lloyd George did it. Winston Churchill did it. And Jack Lynch did it. They all took cabinet papers home and did not return them to the State when their term as government leader ended.
The documents later surfaced in their political papers. In many cases these were documents of considerable historic significance: but in fairness it must also be said that in most cases there would be duplicates still in the State's archives. One of the most significant groups of papers to be released by the National Archives under the 30-year rule this January are some crucial files on Northern Ireland policy which were returned from Mr Lynch's estate after his death. They are being catalogued as the Lynch Papers.
They represent only a small fragment of the copious files on North-South relations which have been released under the 30-year rule.
One feels somewhat humbled by how big the questions are, how fragmentary and tantalising the evidence is, and how little time there is to examine the hundreds of files during the two-day media preview allowed a fortnight ago, with an embargo on publication until January 1st.
So this account of policy on partition in 1970 must be considered with the above in mind. Mr Lynch was inundated with advice from civil servants, mainly from the Department of External Affairs.
He had declared himself interested in fresh ideas on Northern policy in the aftermath of the riots and deaths of August 1969. Some thought Northern Ireland should be truncated. If a revision of the boundary "made the dent we might expect" and especially "if it won Derry", then it was argued that "it should advance greatly the attainment of the ultimate objective".
But this argument - which had been advocated by some since the signing of the Treaty in 1921 - ignored the fact that a smaller, wealthier, more homogenous and more unionist Northern Ireland would surely prove a more formidable bulwark against Irish unity than would the population of the six counties.
A "think tank" was established by the foreign minister, Dr Patrick Hillery. Even its title was significant: "The Interdepartmental Unit on the North of Ireland".
There was considerable agonising about whether the North should be termed the six counties or Northern Ireland. Whichever was in current usage was something of a weathervane concerning Dublin's attitude.
Dr Hillery himself told the inaugural meeting: "While we have spent the past 50 years in building up and opening up our own society to the point where we can deal, with quiet self-confidence, with our own destiny, the North, much to the regret of any Irishman, has managed to dig its own grave." Dr Hillery promised the committee that "we shall see an end to partition within, at most, a generation".
Mr Sean MacEntee, in a private letter to Mr Lynch in November 1969, did not seem so optimistic.
He asked: "Is it politic to claim a sovereignty that one is powerless to assert?" And he was critical of the 50 years of anti-partitionism of which he himself had been one of Fianna Fail's chief exponents: such a "frontal attack" on the Northern position, he admitted, had "failed dismally". It was time for another approach. Mr MacEntee advised that the government should accept the "de facto" position of the Northern government and should "co-operate wholeheartedly with it in every field of common interest".
Although he thought it might be too optimistic, "if we can make a gesture of this kind, the resentment of some `hard-line' unionists in the North at being kicked around by the UK government may lead them to consider seriously your suggestion of a federal arrangement, even if only as a means of freeing themselves from Westminster".
Amid the din, one voice continued to speak with the greatest clarity. Dr T.K. Whitaker, who as secretary of the department of finance had helped to initiate the historic meeting of Mr Sean Lemass and Captain Terence O'Neill in 1965, was widely regarded within government circles as an individual with a keen interest in North-South relations. Although he was by now governor of the Central Bank, his advice continued to be sought by Mr Lynch and his name occurs on the files for 1970 as does his "TKW"-initialled signature.
But in no document does he contradict the succinct advice he had sent to Mr Lynch when the Troubles broke out in the autumn of 1968. And this document is a fair summary of his continuing input: it catches his essential analysis of the problem and his preferred prescription. Had other "slow learners" appreciated its wisdom, the island of Ireland could have been spared much agony in the 30 years which followed.
When Dr Whitaker wrote his modestly entitled "A note on North-South policy," in November 1968, nobody had yet been killed in the Troubles. Since force had long since been abandoned as counter-productive, there was, for Dr Whitaker, only one choice: "a policy of seeking unity in Ireland by agreement in Ireland between Irishmen".
Of its nature this had to be a long-term policy, requiring "patience, understanding and forbearance and resolute resistance to emotionalism and opportunism".
It would be no less patriotic for that and - Mr Lynch was reminded - it was essentially the Lemass line.
Another nationalist myth was next put in context: the notion that a sufficient explanation for partition was that it had all been a British plot. Dr Whitaker was measured. "The British are not blameless, as far as the origins of partition are concerned, but neither are they wholly to blame."
A reading of Irish history revealed "the deep, complex and powerful forces" which had shaped partition. It was "much too naive to believe that Britain simply imposed it on Ireland".
The South also needed to take cognisance of unionist fears of losing the advantages of the British economic subvention, and of their other fear of cultural and religious domination in a united Ireland.
All that could be expected from the British was "benevolent neutrality": Dr Whitaker believed that no British interest would be interposed to prevent unity if the Irish North and South wanted it. But this would be "cold comfort" if we did not also "achieve a good `marriage settlement,' in the form of a tapering-off over a long period of present British subsidisation of N.I".
Dr Whitaker warned that the British could not be expected to expel a loyal Northern Ireland from the UK: rather they were motivated to insist on "the righting of social and political injustice" within Northern Ireland because they wanted "to clean up what they regard as an unpresentable backyard".
Dr Whitaker also warned against any temptation for the Irish government to suggest to the British that the unionists could be "brought to heel by financial sanctions".
The "mere suspicion" that this might be our policy would be damaging to our long-term strategy - and this would be so "amongst Catholics no less than Protestants".
Dr Whitaker was emphatic that the prosperity of both parts of Ireland should be the goal. While remaining dedicated to "the ideal of a united Ireland" we need not "torment ourselves" by the thought "that even Northern nationalists would some day be seduced into becoming happy citizens of the North".
There is nothing in Mr Lynch's handling of Northern policy, whether in government or opposition during the 1970s, which would contradict the impression that he was persuaded of the merits of Dr Whitaker's 1968 analysis and prescription.
Dr Whitaker saw the big picture: all the modern trends were "towards liberalisation, towards greater concern with human rights and conditions, towards looser regional political groupings, towards greater tolerance (or indifference) in religious matters". Such trends "cannot but affect the North; indeed, they are already patently at work".
He insisted that the South "should not be the prisoners of old ideas, even as to the form that re-unification might take". There was a need to be "original and ingenious".
We should explore "all kinds of possibilities - confederation, federation, external association, condominium, the Benelux Agreement, the political integration principles involved in EEC".
He believed "a very special formula" might have to be found. He thought it "unfortunate" that Article 3 of the 1937 Constitution appeared to claim for the South "such a premature and dogmatic right, without reservations as to form, to rule the whole of Ireland". But there was nothing that could be done about this "except to forget it"!
In conclusion Dr Whitaker again emphasised his conviction that there was "no valid alternative" to the policy of seeking "agreement in Ireland between Irishmen".
He was especially mindful that any return to violence risked creating "a deeper and more real partition than has ever existed in the past". Such a partition had been a "real danger" during the course of the 1956-62 IRA campaign "when the people of the North and South almost ceased visiting one another and the Border resembled the Berlin Wall".
When an outline policy was prepared in 1970 to "ease the way" to eventual reunification, there was an acknowledgement of the difficulties posed by "divorce, birth control and other disabilities," bearing in mind that a united Ireland "would be a pluralistic rather than a confessional society".
But while it must be acknowledged that there was increasing realism in acknowledging the shortcomings of the South, Dublin civil servants had a keener eye when listing the failings of the Northern state.
There were two essential considerations to always bear in mind: "the first is that a society whose origin is dishonourable and whose legitimacy is constantly challenged is at a considerable disadvantage in dealing with its neighbours and remains fundamentally impotent".
The second was that Northern Ireland "contains a substantial body of people ardently committed to the preservation of their own personality and peculiarities to the point of suicidal resistance if attacked direct". Given these facts, policy had to be shaped "in the narrow ground between these two basic factors".
There was general acknowledgement that responses to each crisis in the North had to take into consideration Dublin's long-term goal. Dr Hillery, in a scribbled note to Mr Lynch, catches this dimension: he was keen that Mr Lynch should let the incoming British prime minister, Mr Edward Heath, know that "your policy and all you are doing is aimed at uniting the country by peaceful means and not to be interpreted by anyone as co-operation for the purpose of peace only".