On Ulster, Mideast, budget, morality

Contrary to the implications of your editorial ''Bold bid for Irish harmony'' (Sept. 29), the Irish Republic has long since abrogated that part of its constitution which gave recognition to the Roman Catholic church.

Since non-Catholics have enjoyed disproportionately high representation in all fields and offices, including the presidency, the Republic of Ireland might well serve as a model of religious tolerance.

Of much more relevance to the strife in Northern Ireland is the sectarianism of the British constitution, which governs the province. Because of the union of the Protestant Church with the British state, many Ulster Protestants, such as the Reverend Paisley, consider union with Britain as something of a prerequisite to Protestantism. Were the Protestant Church not favored by the British constitution, Ulster Protestants would have no particular interest in remaining British, and one of the causes of deep division in Ulster would disappear.

On the other hand, the exclusion of Catholics from the highest office in Britain, the retention of parliamentary seats for certain Protestant clergy, the oath of allegiance to the titular head of the Anglican Church (imposed on public office holders), are irritants to Ulster Catholics. In the interests of peace, a reform of the British constitution is of far greater urgency than that of the Irish one.