I wanted to find out which way the Foreign Secretary would jump on this choice, when chairing his keynote session to the Fabian Change We Need conference.
And Miliband won laughter from his audience for saying:
"Its either meaningless or dangerous and we don't know which. Neither of those is a good policy. So we need the Conservatives to come clean on whether it is a meaningless or a dangerous policy. But, until you do, you can expect your opponents to attack it as both - which is what we plan to do".
If the Sovereignty Act was simply a symbolic bill, then it could be seen as meaningless. On the other hand, if it was substantive, it could threaten the basis of British membership of the EU.
"Because of the 1972 Act, Parliament has decided that European law has supremacy. On the single market, thank goodness for that, because you can't have a single market where everybody picks and chooses their own rules. But Parliament can change that, by choosing to leave the European Union. We have Parliamentary Sovereignty in this country. So if the Bill is just to restate that, then it may well be meaningless. But if it is meant to make it possible for Parliament to overturn European Law then it is dangerous, because it would be incompatible with the membership of a club with rules which you can't rewrite on your own".
Similarly, Miliband argued that the policy of seeking to open a new round of intergovernmental conferences to rewrite the Treaties could prove meaningless, since it depended on an agreement from other countries both to begin the talks and for all 27 countries to agree the results of a new policy.
But there was also a danger in such a policy, he argued, because there would be a loss of British influence on central issues in the EU:
"If that is how we choose to focus British engagement, then we are not focusing on issues of enlargement, of the budget, and of climate".
I tend mainly towards the 'meaningless' camp. David Cameron's main objective seems to have been the 'long grass' approach of winning five years breathing space from a deeply Eurosceptic party. Ken Clarke seems to be content that it will be a 'meaningless' version of the Sovereignty Act. Beyond sceptical symbolism at home, it seems likely the meat of the policy is being content with living with Lisbon, while attempting to negotiate for changes at the margin, while not picking any 'big European fight'.
But a meaningless policy may contain little political threat. So will the Conservatives' opponents instead stress the dangers of marginalising British influence in Europe be the central message? Their new EU alliances, with almost no west European allies, marginalising the Conservatives from the Merkel-Sarkozy mainstream of the European right provides evidence for this side of the argument.
Miliband does make a strong argument that there is a major opportunity cost to making these politically-led "renegotiations" the focus of Britain's engagement with its EU partners. (Is the balance or content of British/EU employment and social policy the central issue? Should a 'repatriated' British policy should be enormously different in terms of the content of employment rights? If you thought so, you might think Cameron had the right priority).
That seems to me a correct analysis - and the substantive cost of a meaningless policy - but it may prove harder to turn that 'opportunity cost' policy and diplomatic, even if valid, into a clear public political message.