10%+ unemployment... how much power to unions have vis-a-vis state governments, really?

one part question, one part debate-ish topic

do union contracts with government units require legislative approval, or is it run through the executive (with the legislative check being the budgeting process)?

**assuming **the political will is there, (or not necessary) what exactly is the hold up with state governments utilizing their monopsony power to break unions that provide public services?