Britain's election results seem to point in two very different directions. The headline result is that Boris Johnson's Conservative Party has won a smashing victory against Jeremy Corbyn's Labour Party, clearing the way for Britain's exit from the European Union. This would seem like good news for British nationalists, who have treated the European Union as an enemy for decades.

Yet this victory may weaken the political fabric of the United Kingdom. Scottish nationalists did extraordinarily well, too, while for the first time, more nationalist members of Parliament (who want a united Ireland) have been elected in Northern Ireland than unionist MPs (who want the union with Great Britain to continue). This has prompted some commentators to start talking about a united Ireland. But that isn't likely to happen any time soon.

The election results present enormous challenges to unionists, including the dominant Democratic Unionist Party (DUP). The first problem is the obvious one. For the first time, there will be fewer unionist MPs in the new Parliament than there will be nationalist MPs, although nationalist MPs still do not have a majority, because the cross-community Alliance party has also won a seat. This is a problem, because the territory of Northern Ireland was deliberately designed to ensure a unionist majority in perpetuity. (Full disclosure: The author's great-grandfather was the Irish representative on the Boundary Commission that controversially agreed to this border.)

Now, this century-long territorial gerrymander seems on the verge of collapse thanks to demographic and political changes. Nationalists do not enjoy a majority (because of the Alliance Party), but the result tells unionists that they are in long-term trouble.

That isn't all. The DUP had a powerful voice in the last Parliament, because it could demand a price for supporting the minority Conservative government. Under the so-called "confidence and supply" agreement, it was not in government itself, but could demand concessions from the administration, including political concessions on Northern Ireland. That was one reason it was so hard to reach an agreement on Brexit.

The border between the Republic of Ireland and the North of Ireland became a key issue for negotiators, because of fears that reintroduction of border controls could destabilize peace. However, the DUP threatened to veto any agreement that created a separate arrangement for Northern Ireland, in case it damaged Northern Ireland's link to the rest of the United Kingdom. In the end, Boris Johnson effectively abandoned the DUP and struck a provisional deal with the E.U. under which there would be no customs controls between Northern Ireland and the Republic of Ireland, but there would be controls between Northern Ireland and the rest of Britain. Now, the DUP is in a bad situation with little bargaining leverage.

The final problem for Unionists is very simple. Johnson's Conservatives don't seem to particularly care about unionists, and perhaps don't even care very much about Northern Ireland's territorial status. They were happy to weaken Northern Ireland's relationship with Britain to reach a deal on Brexit. They are redefining their understanding of conservatism so that it is based around English nationalism rather than U.K. nationalism. That poses an existential threat to Northern Ireland unionists, who view the United Kingdom as the core of their political identity.

Northern Ireland is entering into a world of nationalist strength, unionist weakness, U.K. government near-indifference, and a Brexit deal that emphasizes connections between Northern Ireland and the Republic at the expense of connections between Northern Ireland and Britain. That might seem to add up to a united Ireland in a hurry, perhaps after a cross-border referendum. However, there are strong countervailing forces.

The first and most obvious of these is that the government of the Republic of Ireland does not want a united Ireland in the short term. It can see very well how Britain's politics have been shattered by a divisive referendum over the country's constitutional status. It does not want to import instability into its own political system by encouraging a referendum in Northern Ireland that would be similarly divisive.

It is notable that Ireland's first response to the election result was to warn against moving to a united Ireland and to express the hope that Northern Ireland's Assembly (which has been suspended due to disagreements between nationalists and unionists) might now be revived. The Republic's government wants a return to stability in Northern Ireland rather than dangerous and unpredictable short-term change.

The second is that the party that really wants a united Ireland and political upheavals in the Republic suffered some setbacks in the elections. Sinn Fein, which was organically linked to Irish Republican Army paramilitaries, did well in capturing seats, but its overall vote fell. It is being challenged again by the Social Democratic Labour Party (SDLP), its more moderate nationalist rival, which won two seats. The Alliance party, which works across both the nationalist and unionist community, made real gains in the election, likely by appealing to more moderate unionists. Sinn Fein's strategy has been to build strength in both Northern Ireland and the Republic, so as to press for a united Ireland, where it could be a powerful force. It failed to make the progress it wanted to make in the last general elections in the Republic of Ireland, and now it is losing votes in Northern Ireland, too.

The result is long-term uncertainty for Northern Irish politics, but little short-term likelihood of a united Ireland. Unionists are uncertain about their future, but there is no strong and unified movement for a united Ireland. The party that most wants a united Ireland is losing popularity rather than gaining it.

Over the long run, increasing economic ties between Northern Ireland and the Republic might make a united Ireland more plausible. But even then there would be controversy: It is not clear, for example, whether voters in the Republic would be willing to pay the higher taxes that would be needed to maintain government services and high rates of government employment in the Northern Irish economy.

Henry Farrell is professor of political science and international affairs at George Washington University. He wrote this article for the Washington Post.