As expected Fianna Fail did poorer in the next general election in February 1948. It lost eight seats in a Dail whose total membership increased by nine (it was curiously argued that a substantial number of Irish emigrants would be returning from England after the end of the war and that the Dail numbers should reflect a population increase, whereas, in fact, the population was decreasing). Fine Gael gained a single new seat and the combined votes of the two Labour groups gained two seats, the farmers group, Clann na Talmhan lost four seats, the new radical republican group, Clann na Poblachta won 10 seats, which was a disappointment given their expectations and their imprudent decision to contest more seats than they could possibly win, and a variety of other independents won 12 seats. The only conclusion from the election was that Fianna Fail had lost the confidence of the majority. Accordingly, a coalition of virtually all other groups was formed, with John A. Costello of Fine Gael becoming Taoiseach. The Fine Gael leader, Richard Mulcahy, still provoked too many civil war and postwar memories to be acceptable to some in the coalition. Sean MacBride, the head of Clann na Poblachta, became minister for external affairs, an appointment scarcely conducive to amicable Anglo-Irish relations.
Significantly, it was the Taoiseach, Costello, rather than MacBride, who broke the news that Ireland was going to be proclaimed a republic and would withdraw from the British Commonwealth, which he did in September while visiting Canada. That took place the following Easter Monday, but the British responded by legislating that Northern Ireland would not cease to be part of the United Kingdom without the consent of its parliament and that the Irish were not to be regarded as a foreign nation nor its citizens aliens in Britain. While the Irish had joined the Office of European Economic Development and were to receive American assistance through the postwar reconstruction measure, the Marshall Plan, MacBride made clear that Ireland could not be part of the North Atlantic Alliance or NATO as long as Britain "occupied" Northern Ireland. That same year all of the Irish political parties agreed to a church gate collection in support of an antipartition campaign that had been started by Northern Irish nationalists, but which now received the endorsement and cooperation of the Irish Department of External Affairs. De Valera, soon after losing power in the previous year's election, had gone on an international tour to the United States, Australia, New Zealand, and India, promoting a similar message.
Historically, the other memorable issue during the first coalition government was the "mother and child" scheme of free publicly provided obstetrical and pediatric care proposed in 1951 by Minister for Health Dr. Noel Browne, a colleague of MacBride in Clann na Poblachta. The measure was partly inspired by the more comprehensive system of national health care that had been established by the Labour Government in postwar Britain. Understandably, it was opposed not only by the doctors' organizations in Ireland but also by the hierarchy of the Catholic Church. The ecclesiastical objections were based on a suspicion of state intrusion into private and familial matters that was grounded in earlier papal social teaching and a belief that there should at least be a means test, so that public assistance should go only to the truly indigent. There was also a fear that many of those administering the program, especially if they received their medical training abroad, would be inclined to promote various practices, such as contraception and abortion, that were condemned by Catholic teaching. When his colleagues in the government, including MacBride, deferred to the bishops, Browne resigned his position.
Curiously, in a general election held soon after, Fine Gael gained nine seats in the Bail fiireann, while a reunited Labour Party lost three and Clann na Poblachta shrank to two. However, Fianna Fail, which regained only one seat, was able to gain supporting votes from a sufficient number of independents to be able to form another government. That government instituted a system of social insurance for Ireland in 1952. The following year the benefits of the earlier-rejected mother and child scheme were extended to all who qualified for the social insurance system. The attentiveness of the Fianna Fail government to Catholic anxieties, however, was manifest in the passage of legislation requiring adopting parents to be of the same religion as the child and its natural parents or the mother, if she was unmarried. Then, in another general election in 1954, Fianna Fail lost a single seat, but Fine Gael gained 10, which, along with the Labour gain of three and the support of other groups and independents, enabled another coalition government to be formed under Costello.
Under this government Ireland finally gained its long sought goal of admission to the United Nations as part of an East-West deal in which Ireland was admitted along with Manchuria. The Soviet Union had earlier objected to Irish membership partly because of its suspicions of Irish softness toward the Axis powers, but primarily because of the ultimately unwarranted suspicion that Ireland would be another Anglo-American pawn in the international body. A census taken at the time also reported that Ireland was experiencing a decline in population, a statistic shared at the time only by the Russian-dominated East Germany (whose fleeing population ultimately was contained only by the construction of the Berlin Wall in 1961) and by communist North Vietnam (many of whose residents, especially Catholics, fled to Western-supported South Vietnam). A great literary debate developed about the "vanishing Irish" and the apparent acceptance by its political authorities of economic and social stagnation under which potential problems were avoided by the outlet of emigration. In such a situation, a few sought an outlet in violent irredentism as the IRA became a violent campaign to "liberate" Northern Ireland in 1956 with a series of attacks across the border on RUC barracks. The campaign would continue, but with greatly reduced activity, until January 1962, when it would be formally called off. The major reason for its failure was the lack of support from within the Northern Irish nationalist or Catholic community, many of whose residents had been benefiting greatly from the economic development of Northern Ireland and from the more generous social welfare and education programs that greatly surpassed those of the Republic of Ireland. Most of the participants in the campaign were from south of the border. One of them, Sean South, from Limerick, even received a virtual hero's funeral after his death in a raid on a police barracks in Fermanagh. No doubt Fianna Fail gained from a ground swell of nationalist sentiment in a general election that followed soon after, as it gained an absolute majority of seats in Bail fiireann enabling de Valera to again form a government, which would be his last, in March. Not surprising, that government had no inhibitions about applying the still existing wartime emergency powers against the IRA, especially that of internment, which effectively broke the back of the campaign.
That government would be the last led by de Valera, who in June 1959 would run successfully for the presidency, defeating a Fine Gael and pro-treaty legendary figure, General Sean McEoin. Significantly, a constitutional amendment to replace the Single Transferable Voting system and thereby benefit the largest party, Fianna Fail, failed, even though its proponents had thought the pro-de Valera vote would carry the amendment along. De Valera, whose age (he was near 77) and declining eyesight made him less able to actively direct government and more suitable for the honorific presidency, was succeeded by his longtime ally in the anti-treaty Sinn Fein and in Fianna Fail, Sean Lemass.