Is desire for secession a growing trend?

Seeing this article this morning ("Elections in Britain Reveal a Scottish Line in the Sand") evoked a thought: as the large nations of the developed world grow older, is there a trend towards decomposition? That is, will we see more secession movements in the 1st world?

The Scots in the United Kingdom are not alone in their slow movements towards secession: Quebec is well known for wishing to secede from Canada; Vermont has a small movement to secede from the United States; the Northern League in Italy has associations with secession; and the Basque nationalist movement has at times violently sought separation.

Within the United States, since at least the 1980's murmurs of "states' rights" continue to percolate, often associated with the apparent desires of the conservative political right to take the fight for many issues to the state level, complicating the ability of liberal politicians to engage the issue from a federal level.

I can make no assertions here, not having researched the subject thoroughly. There are some intriguing questions to be asked, however:

• Is this a real trend within the developed nations, possibly at least a slow-moving one? Or is this merely a defined feature of a nation, such that any given time period always includes a mix of patriots and secessionists?
• Are there common precipitating elements, whether economic, political, ideological, or technology-based?
• If the movement is real, what failures or defects of the large nation-state should be recognized?