The second attempt at an Economics stack exchange is well on its way to a beta release1, fingers crossed.
Having read the Politics vs Economics meta post and the macroeconomics scoping statement; I believe close coordination between the two beta stacks will keep politics out of economics and keep the drier economic theories out of politics.
Whilst I understand a desire to open Politics.SE up for economics questions; there will many out of scope - including many macroeconomic questions that are really the academics' raison d'être; or from questers that simply don't want politically sensitised answers to their question.
So the help page or some supplementary post will need to define a little more precisely what makes an economics question political enough stay here2. This way economics.se can migrate questions to politics.se and politics.se can migrate questions to economics.se with none falling through the cracks or blowing out into long commentary chains on either stack.
1. About a month or two away, give or take last minute definition refinement.
2. And I'll be the first to admit we can see pretty much everything through a political lens when we want to.
On a personal note, I hope politics.se doesn't poach any more economics questions than it needs to; as it'll make the initial growth period of the economics.se beta that much harder.