LONDON — Asked to vote in or out, Britain has chosen decisively to cast off its 43-year-old membership in the European Union, leaving it to face a more complex question: What kind of nation will it be now?

Will Britain be the outward-looking, entrepreneurial, confident country that makes its independent way in the world, as the leaders of the “Leave” campaign insisted it could be?

Or will it retreat to become a Little England, nationalist and a touch xenophobic, responding to the voters that drove it to quit the European Union?

Even more important: Will it even hold together? With Scotland deeply pro-Europe, pressure will increase for another independence referendum that could bring an end to the United Kingdom.