http://en.wikipedia.org/wiki/McCulloch_v._Maryland is 'the' case which explains the existence of the Federal government's implied powers as well as the enumerated ones. For good or ill, the Supreme Court's interpretation of the constitution is the law whenever there's a disagreement, and the decisions of the Marshall court in particular are very important (not least because Marshall was in office for so long so early in the USA's history).

It's pointless to have arguments about the constitution without reference to past controversies - I've highlighted the relevant section here, but this whole page is effectively the 'rest' of the Constitution that lawyers are paid to think about: http://en.wikipedia.org/wiki/List_of_landmark_court_decision... There's a short and very readable book by Prof. Laurence Tribe called 'The Invisible Constitution' that examines the competing approaches to constitutional interpretation and implementation.

Now in California, we do have a very comprehensive state constitution of the kind you're talking about - any significant expansion of state power or rules has to trace its way back to some specific constitutional provision. It's not my idea of an improvement: http://www.leginfo.ca.gov/const-toc.html