Supporters and opponents of Britain's exit from the European Union, outside Westminster Palace in London on Nov. 15. (Adrian Dennis/AFP/Getty Images)

Bronwen Maddox is director of the Institute for Government, a nonpartisan think tank in London.

The lights from Committee Room 14 in the House of Commons were shining brightly onto the Thames on Wednesday night, as more than 300 Conservative members of Parliament packed themselves inside to vote on whether to keep Theresa May as prime minister. After three hours, the news came through: A majority had backed May and she had survived.

Yet it resolves nothing in the great Brexit drama that has brought political life to a standstill and cast uncertainty over the daily decisions of the country, its people and its businesses. May must still get support from Parliament for a deal with the European Union — one that very few members of Parliament of any party seem to like.

Whatever the eventual outcome, Brexit has permanently changed some of the most important institutions of Britain — and continues to threaten the survival of Britain as a nation. It has shined a light onto the weak points of the country’s famously unwritten constitution — and above all the status of the “mother of parliaments,” the badge that the House of Commons and House of Lords have worn for centuries. The risk is that Britain will be permanently weakened in its ability to govern itself.

The most immediate damage is to both the Conservative and Labour parties, at the moment the largest political parties in Britain. They barely function as coherent organizations anymore. Each is deeply divided between voters who wanted to remain in the E.U. and those who wanted to leave. May and Labour leader Jeremy Corbyn have both tried to craft policies on Brexit that bridge these divides, ending up with positions that satisfy few of their supporters. Meanwhile, their lawmakers are not inclined to toe the party line in the traditional way, as some Conservatives’ attempt this week to get rid of their own leader has shown. That matters in a parliamentary system, where the party that commands the greatest support forms the government, but needs the constant backing of its members of Parliament to pass legislation and get anything done.

Brexit has also strained relations between the central government and Scotland, Wales and Northern Ireland. Scotland and Northern Ireland both voted strongly for remaining in the E.U. but England, the largest country in the United Kingdom, voted to leave.

It has been four years since Scotland voted not to pursue independence from the rest of Britain. In that time, the economic attractions of independence have waned — not the least of which was the fall in oil prices and, thus, a fall in revenues from oil drilling off the coast that an independent Scotland might have hoped to control. But at the same time, the political attractions of independence have grown, inflamed by the difference of views over Europe. Scottish independence remains a live issue, even if another referendum on that is not an immediate prospect.

The effect of the Brexit prospect on Northern Ireland is potentially even more destabilizing. May’s early decision that Britain must leave the European Union’s single market and customs union set up a contradiction that negotiations with the E.U. have been unable to resolve.

No convincing way has yet been found to treat goods coming into Northern Ireland differently from those entering the Republic of Ireland, without a system of checks and inspection points on the border between the two countries. Many fear a “hard border” would provoke a resumption of the Troubles, the name given to the decades of violence between those, mainly Protestant, wanting to remain part of Britain and those, mainly Catholic, opposed to government from Westminster.

The border issue has ignited, in turn, the question of whether what will soon be a Catholic majority in Northern Ireland would back reunification if it ever came to a vote. Ireland has shied away from the prospect, both fearing a resumption of violence and conscious (now that it is a comparatively affluent country) of what it has to lose. But the question is in the air all the same.

The greatest damage, however, may be to Parliament itself. The Brexit referendum challenged Britain’s model of representative democracy — in which members of Parliament represent their constituents — by raising above it the direct democracy of a referendum. A majority of MPs have, from the start, appeared to favor closer relations with the E.U. than the result of the referendum implied. The one point on which most members of Parliament now agree is that they don’t want Britain to leave the E.U. with no terms in place — and yet the rules of parliamentary process mean that it could still happen almost by accident, if there is no agreement by March 29.

It is going to be hard for members of Parliament to regain public trust on their fundamental role: trying to win solid public acceptance that Parliament legitimately makes decisions on people’s behalf. The drama of political paralysis, played out night after night on television screens, is not helping.

Read more:

George J. Mitchell: Britain and the E.U. promised no hard border with Ireland. They can’t renege now.

Sebastian Mallaby: The case for a second Brexit referendum

Sebastian Mallaby: Britain faces another political shock. It may matter more than Brexit.

Anne Applebaum: Theresa May’s Brexit deal gives everyone something to hate