The British chancellor's ambition to succeed Tony Blair as prime minister this summer was the most significant of several factors shaping his budget yesterday.
It will not have been lost on Gordon Brown that opinion polls, including one published yesterday morning, indicate that the prospect of him replacing the more pragmatic Mr Blair has actually increased support for the opposition Conservative Party.
Mr Brown's decision to cut the standard rate of income tax, from 22 to 20 per cent, is less likely to reflect the views of a man who is, self-avowedly, on the left of his party, and to have more to do with the rising popularity of the Conservatives.
Similar concerns lie behind the aspect of the budget with the the most immediate impact on the Republic - the decision to cut corporation tax which has consequences for the North's economy and the political drama currently in its end game.
While the cut is something of a sop to the Democratic Unionist Party, which wants UK corporation tax to be made more competitive with rates prevailing in the Republic, Mr Brown's motivation had more to do with demands from the Confederation of British Industry and others to do something about the competitiveness of the UK generally.
A wider package of economic measures aimed at cementing devolution in the North is expected to be announced today. But much of the good in the corporation tax cut has been taken out of it by a 2 percentage points rise in the lower small business corporation tax rate, which business lobbies in the North claim will hit them particularly hard.
However, Mr Brown's parsimony, which is mirrored in the decision to balance the reduction in the standard rate of income tax with the abolition of the lowest 10 per cent rate of income tax, is really about trying to boost popularity without leaving himself open to charges of tax-and- spend.
This juggling act indicates a disappointing focus on short-term political objectives. More encouraging are signs of a growing awareness of how taxation policy can improve health and the environment. These include the exemption of "zero carbon" homes from stamp duty and the reduction of VAT on nicotine substitutes.
Mr Brown's budget shows the politics of tax cuts have not gone away but that they can at least be framed in terms of improving public welfare, something the Irish political parties might bear in mind coming up to the election.