[mem0r1]

The lack of a constitutional court at federal level is in fact a major weakness of the system, there have been several attempts (1999, 2011, ...) to give the supreme court that competency (similar as in the US). Without such a court, the parliament is free to pass unconstitutional laws at their own discretion (which happens from time to time). Referendums are not a very good instrument for ensuring the constitutionality of legislation. Almost no citizen reads a law proposal which for example consits of 50 pages, let alone has the time or ability to ensure constitutional compliance of such. Approval of a particular legislation at a referendum merely signals basic political acceptance and is very much prone to manipulation by media (dis-)information, political advertisments, etc. At least the supereme court de-facto acts as a limited "constituional court" to protect the rights enshrined in the European human rights convention. Very interesting read: Federalist paper No. 78

[m_mueller]

As a Swiss I agree that compatibility with the constitution is a major problem of referendums, somewhat less so of parliament decisions. One measure I'd like to see is to (a) forbid the government to send the people anything other than the proposed legal text (as other material is often very manipulative) and (b) extend the options for answering to yes/no/I don't understand. Third option in enough quantity could then trigger another round of making the text more clear and succinct and then trying again on the next voting Sunday.

[rumcajz]

That sounds exploitable. People would strategically vote "I don't understand" to delay the initiative.

[m_mueller]

Why do that instead of just "no"?

[rumcajz]

Because likely to elicit reworking of the proposal you would need less than 50% of the vote. To defeat the proposal you need at least 50%.

[m_mueller]

you could still deal with that. one option would be to just go for the outcome with the highest percentage, instead of the simple 50% majority.