While not only democracies are legitimate (departing from Weber: traditional and charismatic legitimacy) democracies do have what I would call "face legitimacy." Look at our SWORD Model article in the Journal - especially at the Host Government Legitimacy variable in Table 3. The first varible in the table specifically relates to democracy (electoral). Corruption is a classic driver of insurgency or, simply, electoral turnover. As long as you can throw the rascals out by election there is no need for armed rebellion. Same with "motivation of the people" which here refers to the ability of the government to deliver the basic "goods & serices" such as security demanded by the people. The last of the most important variables really asks if there are alternatives to political violence such as free, competetive elections. If all these are present one is dealing with a democracy and that democracy is perceived as legitimate by its population. Given that legitimacy is the single strongest internal dimension explaining the outcome of an insurgency, then it seems clear that deocracies will generally defeat insurgencies directed against them. The correlation should range from very high when using a rigourous definition (criteria) for democracy to high for a less rigorous formulation.

Cheers

JohnT