LET us begin with a confident but falsifiable prediction. The Maya 1st, 1997, Westminster election is likely to be the last such election in which the unionist bloc wins an overall majority of the votes cast in Northern Ireland, even if there is no reform of the electoral system for the United Kingdom parliament.

Our prediction is based on the results displayed in Table 1. In the three region-wide elections in 1996-1997 the average share of the vote of the Unionist (U) bloc was 50.3 per cent. The U bloc, the Ulster Unionist Party (UUP), the Democratic Unionist Party (DUP), the United Kingdom Unionist Party (UKUP),: the Progressive Unionist Party (PUP), the Ulster Democratic Party (UDP) and the Conservative Party, is distinguished by its ethnic Protestantism, and its reluctance to share significant power with nationalists.

That is why supporters of the Alliance Party are not part of the U bloc. Alliance supports the Union, but draws small-scale electoral support from both Protestants and Catholics. It promotes power-sharing, favours co- operative relations with the Republic, and presents itself as a bridge- builder.

Provided one condition is met, Table 1 suggests that Alliance will be able to play its self-professed role at the beginning of the next century because it will hold a pivotal electoral share of votes. The condition? That the proportion of the electorate which belongs to cultural Catholic families continues to rise.

Our prediction does not imply a complete reversal of fortunes for unionism. The U bloc's loss of an overall majority of the future electorate will not mean that the nationalist (N) bloc will immediately enjoy exactly what the U bloc loses. The N bloc is growing (see Figure 1) but it cannot become a majority bloc for another two decades.

A long re-equilibration will give the APNI its bridge-building opportunity. In the next century its role across the region as a whole will be the same as it now has on Belfast City Council, e.g. deciding whether "parity of esteem" between the two national traditions or "a neutral environment" is the best way of managing the insignia of public institutions.

SLOW but seismic shift is taking place in the balance of electoral power. The proportion of cultural Catholics was at least 42 per cent in the 1991 census, and has continued to expand. This shift is making itself felt electorally, and is especially evident amongst younger cohorts of voters.

All nationalists are the beneficiaries; although Sinn Fein, so far, is benefiting more than the SDLP. In a survey we conducted for RTE's Prime Time in May 1996 almost 60 per cent of Sinn Fein's support came from the 18- 34 age cohort, three times the level of support the party enjoyed amongst respondents aged 55 or over, a pattern consistent with evidence from other survey data.

In the last year Sinn Fein has averaged 16.5 per cent of the vote, compared with its 1982-1994 average of 11.3 per cent. It has gained from demographic change, and from what is optimistically called the first peace process.

The big picture for Northern nationalists is simple. In the next century they will be in control of their destiny. Unionists will not be able to govern them, though they may govern with them. Nationalists have little to fear from a new devolved government. It is exceedingly improbable that any new Northern assembly can become a tyranny of the unionist majority, a second Stormont. Nationalists will not have to rely solely on the constitutional protections promised in the British Framework document: these will be supplemented by the political security of their electoral weight.

The recent elections also reveal a significant fragmentation in the unionist vote. "Other unionists" now attract an increasing share of the vote, though none of these fragments can, as yet, hope to displace the UUP or the DUP.

There are two political reasons for this fragmentation. The first is the uncertainty amongst unionists about the best strategy to pursue in the face of the British and Irish inter-governmentalism established by the Anglo- Irish Agreement, re-expressed in the Joint Declaration for Peace, and given detailed institutional form in the Joint Framework documents; whence the rise and fall of the local Conservative party, and the zig-zagging of Mr Robert McCartney's UKUP.

The second is the electoral emergence of two small loyalist parties, the PUP and the UDP, in the wake of the official loyalist paramilitary ceasefires in October 1994.

Despite this fragmentation, in 1997 Unionists, as always, co-operated with one another more in Westminster elections than did nationalists, with the smaller parties withdrawing candidates where they feared a nationalist might otherwise win.

But this pattern may not continue. A second peace process would result in an agreement amongst nationalists to have electoral pacts for Westminster elections. A pact was promoted by Sinn Fein during late 1996 and early 1997 but was turned down by the SDLP because of the IRA's resumption of violence.

Indeed, if the British Labour government introduces proportional representation for Westminster elections then nationalists will not need to co-operate to deprive the UUP of its "surplus" seats; and the share of seats won by nationalists would rise in proportion with their votes, with or without a second peace process.

Unionism therefore faces an electoral crisis. The U bloc will soon be an electoral minority in the region, albeit the biggest one; and it is likely that all regional elections will soon be by proportional representation.

THE electoral crisis of the U bloc has been less noticed than the loss of Mr David Trimble's UUP's grip on Mr John Major's government.

The Labour government has a manifesto commitment to the Framework Documents, which it will pursue with or without Sinn Fein's presence at negotiating tables.

Dr Mo Mowlam's and Mr Tony Blair's actions spell out a simple message: Northern Ireland remains part of the United Kingdom for as long as a majority wants, but the U bloc has no veto on reform, or indeed on the North's relations with the Republic. This message so far is better understood by some parliamentary unionists than it is by the more cognitively-challenged sections of the IRA.

Unionists face a very difficult transition as the second millennium beckons: a Labour government and its allies could control Westminster for a decade; a Fianna Fail-dominated coalition may control Dail Eireann for five years; at the negotiating tables the agenda will be "Frameworked" irrespective of the presence or absence of Sinn Fein; and against this background unionist demographic and electoral power is slipping.

Time will tell whether in the twilight of the second Protestant ascendancy sufficient unionist reformers emerge to carve out a political settlement with their nationalist rivals. That would be highly desirable. It would be more likely to happen if all republicans understood that the IRA's war is neither moral nor necessary.