There is at least one terrible, terrible prospect emerging as this campaign grinds on, and that is that voters have already made up their minds, that no huge event — a crash, either of shares into the floor or planes into buildings — will supervene, and that Obama will maintain a solid 4-6% lead until November, and take the White House with 290 to 300 plus electoral college votes.

Every poll suggests this is a real possibility, since the sheer ineptitude of the current administration has rendered party politics more visible than it usually is in the American polity — the clear majority of independent voters simply want the Republicans out, and a not inconsiderable number of registered Republicans agree with them.

Should this come to pass, the US election will be much like the Australian one —  the numbers will shift around a fixed point and the Murdoch press will debase itself manufacturing crises to no avail — with the important difference that it will be THREE TIMES AS LONG.

So instead, let’s look at a couple of alternative scenarios — the most interesting being what happens if Obama’s numbers track in susbtantially for whatever reason, and the election becomes a genuine toss-up.

For Obama, such an occurrence would summon up a nightmare scenario: a second Democratic loss to Ralph Nader.

Nader’s stocks have been, until recently, lower than Starbucks. His decision to fight the 2000 election was keenly debated by the 7-8% of Americans who would call themselves “Left” (with a capital L) rather than “liberal”. About a quarter of these are outside of the system altogether — anarchists and radicals who would never vote, or register. Another quarter believe that the fight should always be conducted within the Democratic party, and that select Congressional and Senate races should be the focus of campaigning once a left presidential candidate has been inevitably defeated.

The other half can be persuaded either way. Nader took a fair slice of them in 2000 — 2.7% of the vote — when the party gave a pre Inconvenient Truth VP Al Gore his presumptive nomination. Florida, the Nader effect and the subsequent four years concentrated minds so wonderfully that one section of the left — Michael Moore most prominent among them — was backing General Wesley Clark for the nomination, as the man most likely to beat Bush in a national security election.

Nader’s decision to run again was greeted with a dismay and anger way beyond 2000, none of it much mollified by the collapse of his vote to 0.3%.

Obama has been relying on the desperation for change, and the personal odium of Nader, to disregard any nuisance from the left. But what if he’s been hubristic about their loyalty to regime change? Considered that way, a Democratic nightmare emerges.

Should that happen, it’s worth looking at the numbers Nader racked up in 2000, when he took 2.7% nationally. In Iowa, for example, off a base of 1.3 million votes, Nader took 30,000. Bush won the state by a mere 3,000 votes. In Wisconsin, Nader took 94,000 votes, pushing Gore back to a mere 5,000 vote victory.

In Colorado, a state Obama is hoping to win, Nader’s 2000 vote was 90,000 on a total of 1.7 million. Bush took the state by 150,000 votes. In Michigan Gore won by 200,000, but Nader took 85,000, in Ohio, 120,000 votes, with Bush taking a 170,000 victory. And of course we all know about Florida.

The threat is greater than it would otherwise be because Obama is pursuing a strategy which counts on a more fluid electoral map than hitherto. Should it come down to the wire, wins in Iowa, Colorado, New Mexico, Nevada, Montana, and Virginia are a possible alternative route to the White House should either Florida or Ohio, together with Michigan, be lost to the GOP.

Yet all those smaller states are areas where an angry grassroots Left for Nader (plus the Greens) could scrape together the few thousand votes necessary to put McCain over the line.

What would happen then, god knows. You would certainly have to fear for Nader’s personal safety. And the sense of lingering bitterness at a dynamic transformational campaign that threw it all away would be so corrosive to Left participation in the mainstream that the Republicans would be poised to fill the vacuum, with a second conservative coming.

Couldn’t happen of course. That’s as likely as control of the world’s largest nuclear arsenal depending on one poorly designed ballot in one county.

On the Republican side, the prospects of an upset are less interesting — unless, late in the day, either Ron Paul or a credible conservative Christian run as a third-party candidate, which seems unlikely.

However there is one hole-in-one fluke forseeable as a possibility. New Hampshire, the one New England state Obama could lose, has become a libertarian focus because of the “Free State project” a nationwide call for 20,000 libertarians to move to one small state and create a critical mass sufficient to influence its politics.

New Hampshire was chosen by online ballot, and several hundred politically active vanguard free-staters have already moved there.

Now consider this scenario: set aside New Hampshire, presume a close race. Obama takes the 2004 Democratic set, plus Ohio (and minus NH). McCain takes the 2004 Red states, minus Ohio, but including Florida. That leaves McCain with 266 electoral college votes and Obama with 268. New Hampshire, with four, makes the difference. A few thousand, or even hundred, low-tax, no-tax, emigres could swing it Obama’s way, at which point one suspects their belief in gun ownership will be vindicated.

Yeah, it’s unlikely. The thing will break a half dozen other ways before it breaks like this.

But wouldn’t it be funnnnnnnnnnnnnnn?