Data: Singular or Plural

The data indicates we have a problem. The data are bad.
What is it? Is data singular or plural?
Going strictly by the latin roots, data is the plural of datum.
However, roots only get you so far. After all, "peas" is supposed to be the singular. However, since peas just sounded like a plural, a singular "pea" was manufactured.
Similarly, to non-scientist types, "the data is bad" sounds better than "the data are bad."
To a scientist, however, data really are a collection of individual data points. A single "datum" could be identified and checked for accuracy.
For a lay-person, however, the individual datum is long since lost in a layer of abstraction. The "data" is now a collection of abstract information, similar to the atmosphere. Sure, the atmosphere is a collection of individual molecules; but, it is a noun referring to the collection, not to individual molecules. Similarly, in common usage "data" has become an abstract collective. Thus, "the data is" becomes a correct way of referring to the abstract collective. The "data are" will slowly find itself limited to the area of scientific jargon.