When was the last time two genuinely democratic countries went to war?

[WMS]

Here's one I thought of: The Arostook War, although that was actually fought between a US state and Canadian province, Maine vs. New Brunswick. Of course no one died.

How about that war in Central America that started over a soccer game?

It is questionable whether either El Salvador or Honduras were democratic countries in 1969, although the odds are better for Honduras being one than El Salvador being one...