David Cameron appears to be playing, as his last card in the election campaign, the visceral dislike of English people for the Scots. This is a bit rich, since his ancestors were clearly not only Scots, but notorious Jacobites: if Donald Cameron of Lochiel hadn't led out his clan to support Bonnie Prince Charlie, the Jacobite revolt of 1745 would never have happened.
Furthermore, Cameron said it was "unprecedented" that a minority nationalist party should hold the balance of power in Parliament. This was completely incorrect. Gladstone's last two governments in 1886 and 1892, and Asquith's government from 1910, saw the Liberals dependent on the support of the Irish Nationalists. This did not lead to governmental chaos: the price the Irish Nationalists demanded for their support was, of course, Home Rule for Ireland, and they were certainly not going to bring down the government until this was safely on the statute book. It is important to realize that Home Rule was not full independence: it was merely a form of devolution, not too dissimilar to that enjoyed by Scotland and Wales today.
There was a continuous constitutional crisis after 1910, but this was the fault of the Conservatives (then more generally called the Unionist Party). There was some disquiet amongst Irish Protestants at the prospect of Ireland being ruled by the Catholic majority. The Conservatives could have calmed such fears by pointing out that Home Rule was no big deal, since the Westminster Parliament could still prevent any Home Rule government from doing anything too drastic, but instead they were so keen to get rid of Gladstone, and then of Asquith, that they deliberately exacerbated Protestant anxieties, with the famous slogan, "Home Rule means Rome Rule". As the Conservative leaders said, "The orange card is the one to play", and the Orange Order in Ulster, which had been moribund for decades, was now revived with Conservative encouragement.
Gladstone's two Home Rule bills were duly killed, after 1910 things went much further. The Conservatives held up Asquith's Home Rule bill in the House of Lords for as long as possible, and implied that it was in some undefined way "unconstitutional" for the Liberals to maintain their Parliamentary majority through Irish support (we shall see whether Cameron will develop a similar argument in the future). Some of the more extreme Conservatives even accused Asquith's ministers (who included that strong supporter of Home Rule, Winston Churchill) of "treason". But if anyone was guilty of treason, it was the Conservatives, because they deliberately encouraged Protestant Ulster to prepare for an armed revolt against Home Rule, even importing arms from Germany with the connivance of the local police. By 1914 civil war looked likely.
Britain was saved from civil war by the outbreak of the First World War, when Home Rule became law but was postponed until peace should be restored. Many Irish were disappointed, and the consequence was the Easter Rising of 1916 and the violence that followed. A very large proportion of the blame for this must be placed on the Conservatives and their deliberate sabotage of moderate Home Rule proposals. The leader of the Ulstermen, Sir Edward Carson, said in his embittered old age that the Conservatives had never really cared about Ulster at all: they merely wanted to make life difficult for the Liberals. One can only hope that David Cameron will act more responsibly than his predecessors!
A Conservative spokesman recently argued that they were the party of opportunity, citing the fact that they had been led by Disraeli, a Jew, and Bonar Law, the only Prime Minister to have been born outside the U.K. (he came from Canada). But this should be approached with caution. Disraeli was very proud of his Jewish ancestry, but he was technically a baptised Christian (without which he would not have been allowed to enter Parliament at the time), and he appears personally to have had no religious beliefs at all. He was a charming and charismatic personality, but without any clear political principles. Bonar Law was chosen as Conservative leader in 1910 solely because of his intransigent opposition to Irish Home Rule. He encouraged the Ulster Protestants to arm themselves to fight against it, and even suggested that the British army should refuse to obey if ordered to coerce Ulster. He is not a good example to be followed.