From an MSNBC.com report on the second bridge bombing in Iraq in two days:
Targeting all transit systems
Paul Kane, a fellow with the International Security Program at Harvard Universitys Kennedy School of Government, said the attacks on bridges are an extension of earlier insurgent attacks on “electric generation sites, infrastructure for water and also the obvious target of oil pipelines.”
Kane noted that Iraq does not have railroad service so insurgents “may be at the end of the transit list. If anything, it means theyre trying to be creative and theyre running out of targets.”
Riiight. They might not know what else to bomb! Finally, they’re getting around to the bridges. Once they’re done with those final targets, they’ll be stumped and give up.
Now, I’ve never attended or taught at or been a fellow of anything with an “International Security Program”, but I always heard that the best way to impede the movement of your enemy’s ground forces was to control or destroy the bridges, what with rivers being natural impediments to the movement of infantry and most vehicles.
It’s one way to prevent forces and supplies from being brought to the front. Alternatively, if bridges behind an enemy can be taken out, you can cut off retreat.
But I’m sure in this case it’s just a lack of targets for the insurgents.