In most cases, however, the meaning is clear enough.  We even have different forms of 'is' to make the meaning clearer if we need to.  The plural form of 'is' is 'are'.  The future tense of that form is 'will be'.  When you say 'are' it means now not later.

So, outside of the philosophico-linguistic puzzles that vexed the likes of Frege, Russell, and Wittgenstein, there's very seldom any confusion about the meaning of 'is' and its conjugates.  That is why Bill Clinton's infamous utterance "it depends what the meaning of 'is' is" has come to symbolize Washington double-speak, because when someone wants to start parsing 'is' you know that you're either not getting straight talk or you're getting a Wittgensteinian deflation of a philosophical conceit.

So, I'm just wondering whether anyone else noticed that Mr Straight-Talk(tm)'s campaign invoked a defense that is emblematic of double talk today when they issued a missive threatening to parse the tenses of 'is' to explain McCain's ignorance about troop levels.  The McCain camp is saying that McCain didn't mean what he plainly said because he might have had a different meaning of 'is' in mind.  Gotta love that straight talk. . .  though it shouldn't take mastery of the Tractatus Logico Philosophicus to comprehend.