MICHAEL McDowell, Pat Rabbitte and Trevor Sargent walk into a bar.

It's an unusually warm May night and the polls are closed.

Bertie's over at St Luke's figuring out who to choose as coalition partner, so the three party leaders stroll into Fagans to wait.

McDowell swaggers up to the bar: "Thanks to the Progressive Democrats, we're not only free from the nanny state and church telling us what to do, but we're rich enough to stand our round. A bottle of your finest French champagne! To liberty!"

Not to be outdone, Rabbitte saunters to the rail and wryly declaims: "Thanks Michael, but Labour thinks the good times shouldn't be for the few. Let's redistribute that wealth. Pints for everyone in the house! And put it on McDowell's tab. To equality!"

They both look at Sargent, who produces two chilled stainless steel flasks from his knapsack and mixes a perfect dry martini, then adds two olives. They stare. "What on earth?"

"Distilled in my garden shed under the compost, cooled with power from the local windfarm, and the organic olives grown in a greenhouse in Wexford and shipped up with a biodieselpowered lorry, " explains Sargent after a long pull. They sniff. "I don't know if you've noticed, lads, but there's no electricity because the ESB are screwed, and when we told you we needed renewable energy, the PDs said it would hurt the economy and Labour said it would hurt the trade unions." They notice the candles, the fact that the fridges are off and that the punters are guzzling Sargent's homebrew with gusto.

"At least my way, we get to keep drinking. To sustainability!"

Well, it ain't Dara O Briain, but you get the idea.

Green isn't a joke anymore.

Green is the new black. Even in the US, where Al Gore's climate movie has proven to be Silent Spring for slow learners, Green is the new red-white-and-blue. Seems every car Detroit's pushing is a hybrid, every CEO's annual report reckons with the company's "carbon footprint" - a term that made most giggle a year ago - and the smart venture capital is flooding into renewables technology.

Check out the stump speech of every presidential candidate. They're all shades of jade.

Something is going on.

It could be that we're entering the third age of Enlightenment politics. The first, 1776-1917, was the Age of Liberty. Next came the Age of Equality, where that value's moral appeal drove revolution and reform worldwide until around 1989.

After nearly 20 years of bloody debate, could it be we're entering the Age of Sustainability?

We may find out in May. I found Irish politics confusing until Michael McDowell unveiled his Rosetta Stone - the smaller party in coalition is the "meat in the sandwich."

The smaller party's ideas give a government its flavour. A brilliant insight that frames this election - but one not necessarily to the benefit of the PDs. Any of the smaller parties could use the argument. Labour could go in with either FF or FG if their trump value, equality, seems appealing.

My money at this point is on the Greens, who saw their support double to 8% in a recent poll. Their policies don't all have to make sense.

The voters just have to intuit that we'd better all take our Green medicine - public transport, windfarms, biofuels, energy-efficient buildings and homes - trust Fianna Fáil (or Fine Gael) to sugarcoat the pill a bit and hope the market does the rest. It's a great deal for both parties. FF or FG gets to blame John Gormley for anything unpopular that they have to do, and the public can trust the Greens to prod the bigger party into doing the right thing for the planet and our children in the way that the PDs did on the economy, jobs and taxes.

If the Greens realise that the economy has to keep growing to pay for it, Ireland might continue to be lucky in a green tech-led Celtic Tiger 2.0. The alternative being an Ireland deserted by evermore multinationals because our island economy doesn't look, well, sustainable.

No laughs? Tough room. I'm here every Sunday. Remember to tip your waitress.