Alexander Van der Bellen, a former economics professor who once led the Greens party and is now running for president of Austria, recently told me that “since the tragic Brexit decision, the sense of belonging to the E.U. suddenly moved to the forefront” in his country.

His opponent, Norbert Hofer of the right-wing Freedom Party, has emphasized allying with Austria’s once-imperial territory in the four-nation Visegrad Group — the Czech Republic, Hungary, Poland and Slovakia. Different as they are, both approaches underscore that Europe is important.

In Copenhagen, the Danish capital, the sense is similar, while exceptionalism remains.

Denmark approved the Maastricht Treaty, which essentially established the European Union as it is now known, in 1993, only after rejecting it and negotiating four opt-outs — including waivers for the euro and defense.

The Nordic neighborhood illustrates Europe’s adaptability. Like Denmark, Sweden is part of the bloc but does not use the euro. Norway is a nonmember but pays heavily for access to the union’s single market. Finland is in the bloc and uses the euro. Neither Finland nor Sweden, both neutral, are part of NATO; Denmark and Norway are.

But the Europeans are no pushovers. Once Prime Minister Theresa May said Britain planned to begin withdrawal talks by the end of March, the leaders of Germany and France — both facing elections next year — responded swiftly and sounded united.