Speculation about election dates is a pretty fruitless business.

The decision will be made within a very narrow circle, and there’s nothing the rest of us can do to influence it; we’re all just guessing. But the guesswork won’t go away, so let’s try to make it interesting by questioning one of its key assumptions.

Although 8 December is the latest practical election date, commentators often remind us that the theoretical latest date is 19 January 2008, and occasionally someone suggests that a prime minister who felt sure of losing anyway might just be bloody-minded enough to hold on to the very end.

But a truly bloody-minded PM — at least one with a majority in both houses — would actually have options well beyond 19 January.

When we say we have three-year terms, that means that “every House of Representatives shall continue for three years from the first meeting of the House, and no longer” (Constitution, s. 28). The existing House of Reps will therefore expire on 15 November this year.

However, all the Constitution says about election dates is that writs for an election must be issued within ten days of the expiry of the House (s. 32), and the new parliament must meet within 30 days “after the day appointed for the return of the writs” (s. 5). The intervening timetable, which says when the election must actually be held, isn’t in the Constitution, only in the Electoral Act .

So a government with control of both houses could amend the Act to string out that process for many months — provided it was granted supply beyond November and didn’t need parliament for any other purpose.

Section 6 of the Constitution requires that there be less than a year between sessions of parliament, so the election would have to be held in time for a new parliament to sit in November 2008. But that still means it could be delayed until October next year, and John Howard could extend his term twelve months beyond what most people expect (although a half-Senate election would have to be held before June).

An interventionist high court might well strike down such a tactic for violating the Constitution’s implied guarantee of representative government. But it’s hard to see the current crop of justices being so adventurous.

No, it won’t happen; the election will certainly be this year. But it’s worth noting we have some constitutional gaps that should be filled. (For more detail on the rules, the parliamentary library has an excellent summary here.)