I'm not a Dunstan fan by any stretch and will vote for Prenzler. That being said the Corp of Engineers is the most egotistical, hard nosed group of morons in any public sector.
Project labor agreements are common now. They DO NOT prohibit non-union contractors from working on government projects. They simply form a partnership between he unions and the contractors that require a percentage of the workers on a public job be from LOCAL union halls. That's how you grow local economy and keep residents in the area.
If the Obama administration has stated that PLA's are legal within federal bidding, then they should do that especially in a depressed work area like ours.