Your first example is in the subjunctive mood; the second is in
the indicative. The subjunctive refers to "a mood of verbs
expressing what is imagined or wished or possible." That's taken
directly from NOAD, and you may be interested in their usage
note: USAGE These sentences all contain a verb in the
subjunctive mood;: … if I were you;: the report recommends that
he face the tribunal;: it is important that they be aware of the
provisions of the act. The subjunctive is used to express
situations that are hypothetical or not yet realized and is
typically used for what is imagined, hoped for, demanded, or
expected. In English, the subjunctive mood is fairly uncommon
(esp. in comparison with other languages such as French and
Spanish), mainly because most of the functions of the
subjunctive are covered by modal verbs such as might, could, and
should. In fact, in English the subjunctive is often
indistinguishable from the ordinary indicative mood since its
form in most contexts is identical. It is distinctive onl