I need help understanding the EU and deficits:

Part 1: What was the purpose of this criterion and how does it benefit the European Union as a whole (but within the context of lower deficits and public debt levels on the member countries' ability to borrow.) What are the advantages and disadvantages of such a rule? Specifically, how can this criterion constrain the behavior of politicians and how does it influence the ability to conduct fiscal policy in response to adverse economic shocks? When shocks take place, are they likely to impact all countries equally?

To help, the rule required countries adopting the Euro to have "sound and sustainable public finances", defined as a government deficit that was not higher than 3% of GDP and government debt that was not higher than 60% of GDP.

Part 2: The Debt Board can be fashioned after the model of the European Central Bank, which oversees the Union's monetary policy. Compare this alternative arrangement with the Maastricht Treaty rules and explain whether a Public Debt Board may be an improvement or not. Please explain your logic in detail