Republican legislative leaders are threatening to ban certain labor agreements they say give an unfair advantage to unions. The issue grew out of a proposed agreement Polk County is considering for the Iowa Events Center that would set a wage for workers in exchange for a no-strike pledge. Senate President Mary Kramer of West Des Moines says that gives union crews an unfair bidding advantage over non-union crews. She says that’s not what they envision when they passed the bill.The Iowa Events Center won a large grant from the state “Vision Iowa” program to help fund the project. Kramer is worried the deal will kill the project.Stefan Gleason of the National Right to Work Legal Defense Foundation says his group will sue if the agreement goes ahead.Senate Democrat leader Mike Gronstal says the agreements are common across the country and do not threaten Iowa’s “right to work” law. Gronstal says most of it is “smoke screen” that republicans are using to “gin up some of their base and get them excited.”Gronstal says Polk County is making the right decisions for the project, and state lawmakers should stay out of it.