The European Union's own Eurobarometer poll released in Brussels on July 17 shows that support for the enlargement of the EU has declined in statistically significant amounts in Italy, Denmark, Sweden and Spain. And it has fallen as well, albeit by a smaller amount, in Germany and Belgium.
As a result, there are now clear popular majorities against enlargement in Germany, France and Austria.
At the same time, the poll found increases in public support for enlargement in Great Britain and Ireland. In the latter country, the poll showed that 59 percent of the population now believes the EU should take in new members.
Overall, support for enlargement across the EU now stands at 43 percent, down one percentage point from an earlier Eurobarometer sample taken last fall.
These shifts in sentiment are relatively small, and come at a time when the issue of EU expansion is not at the center of public discussion. As a result, they may not point to a significant shift in public attitudes in overall support for enlargement. Nor do they suggest that any one member government is likely to change its position on this question.
But nonetheless, behind these popular attitudes is a fundamental divide at both the public and governmental levels about the enlargement of this and any other international organization.
Some existing members clearly believe that they will benefit more if the organization expands, increasing its size relative to other actors on the international scene and thus making member states more influential.
Other current members, however, take just the opposite position. They fear that expansion will either impose new burdens on them, in that they will be called upon to pay for bringing the new members up to the standards of the organization, or that enlargement may dilute the meaning of the institution they are part of by reducing its operational principles to the lowest common denominator.
Because of its aspirations to become a genuine union of states, the EU is especially likely to be the subject of such debates because both supporters and opponents can point to very real costs and benefits involved in any decision about whether to take in new members. And those countries that are already inside know how much the EU has already changed because of new members admitted in the past.
But other international organizations, such as NATO, face a similar problem. If they expand, they may either become a more significant actor on the international scene or they may lose their original meaning as current members are forced to modify the organization in the process of taking in new members.
That is what happened when NATO enlarged itself to include the Czech Republic, Hungary and Poland. Not only did the alliance explicitly say that it would not base certain weapons systems in the new members, but it gave Russia a voice - if not a veto - in some of the alliance's central councils.
Debates about further expansion are therefore likely to reflect tensions between those who would broaden the institution by taking in new members and those who would deepen it by seeking to build up ties among current ones.
The existence of such debates is certain to be exploited by those outsiders who do not want the institution involved to flourish. Some will simply oppose expansion openly, concerned that growth by itself will make either the EU or NATO more significant than it was in the past.
But other outsiders who oppose these institutions may take a different tack, promoting, or at least not obstructing, expansion precisely in order to force the international groups they oppose to change themselves by growing in size.
And that opposition, which may look to some like support, is likely to also play a role in public debates on expansion within the current member states.
As a result of these complexities, the poll numbers in support or in opposition of expansion are likely to move up and down. And the governments that must make the decision about expansion are likely to find themselves in a situation where polling data will not provide an easy answer as to what is the best course for either individual countries or the organizations of which they are members.