Thirteen years ago, I stood in our half-finished house with a toddler on my hip talking on the phone to our editor at the Nation about Labour’s landslide victory after eighteen years in the wilderness. I was elated; it was May Day; I had my red dress on. Though I knew Tony Blair’s campaign was built on spin and calculation, that the party had abandoned its old base to win back Conservative voters, that the manifesto (I wrote then) was “a pageant of small promises backlit as big ideas,” the thrill of watching the hated Tories go down in spectacular flames was delicious beyond words. Katrina put the late, great radical writer Daniel Singer on the line. “You’ll write what you want,” he said. “But I’ve seen it all before, in France with Mitterand. It’s not going to be good.”

The toddler is now a teenager, the paint is peeling again, and we’re older and sadder, too. Daniel, of course, was right. After 13 years of Labour, the gap between rich and poor has widened, civil liberties have been chiselled away, bureaucracy has burgeoned, we’ve fought an immoral war at George Bush’s behest and been complicit in illegal detention and torture. Many people feel betrayed and—worse—disconnected from politics. In the last hours before tomorrow’s general election, Labour is fighting for second place with the Liberal Democrats. The “Clegg effect” has changed the landscape, possibly for ever; for the first time in decades there is a credible third force in British politics.

But still, I am not sure which way I’m going to vote.

If I was voting in a district where a Tory might get in, I would know what to do. But in our constituency, a tired but left-wing Labour MP who opposed the Iraq War—former actor Glenda Jackson—is defending her seat against an energetic, local, progressive Liberal Democrat. The Lib Dems are to Labour’s left on many vital issues: reforming Britain’s hopelessly undemocratic electoral system, civil liberties, breaking up the banks a la Glass-Steagall Act, progressive taxation (though you’d have to crunch a lot of numbers to be sure), immigration and asylum, not renewing Britain’s antiquated nuclear deterrent.  The Guardian and its Sunday sister, The Observer, have both broken with a tradition of more than twenty years to endorse the Lib Dems, on the grounds that electoral reform is now the most pressing issue. (Most readers who commented on the endorsements were enthusiastically grateful; some spoke of “betrayal” and cancelled their subscriptions.) Why, then, am I hesitating to make the leap and vote Lib Dem myself, even in a constituency where the Tories are in third place?

For all its betrayals Labour remains the party of the poor, including the many on low incomes who don’t vote, and the party with the deepest commitment to public services. In the economic crunch that’s coming—the European Union  warned today that the UK budget deficit is set to surpass Greece’s—they are the most likely to make the inevitable cuts with some regard at least for fairness and compassion. Despite—or because of—Nick Clegg’s meteoric rise, we don’t know yet who the Lib Dems really are, or what they care about beyond electoral reform. They are part of the new, more fluid politics (which Cameron likes to pretend he also represents, though in fact the Conservatives remain the party of the wealthiest) based on issues and voter appeal instead of community interests and class allegiances. Their promises sound good, but they also feel somehow callow, as if (as Gordon Brown said in the leaders’ debates) they’d been sketched out on a napkin over dinner.

On the other hand, the Lib Dems represent (as the pundits keep on saying) a once in a generation chance to change the face of British politics—and a chance to vote for a leftish party uncontaminated by Labour’s triangulations and the compromises of power. Like many left-of-centre voters, the outcome I most want is a Labour/Lib Dem alliance: Labour for ballast, experience, commitment, Lib Dem for democracy, civil liberties, independence. Unfortunately, that isn’t an option on the ballot.

Nick Clegg says we should “vote with our hearts for the change we want to see,” but in many seats the voting system makes that a risky course of action. On current predictions, we are likely to end up with a hung parliament in which the Tories have a plurality but no absolute majority. In theory Clegg could choose to side with Labour—though if Labour comes third in the popular vote Clegg won’t, and  shouldn’t, help Gordon Brown stay on in Downing Street. Or he could prop up a minority Tory government—in which case we don’t know how much ground he would give in return for grudging concessions on constitutional change.           

So I’m left second-guessing opinion polls: if Labour still stands a chance of coming second, should I back them in the slim hope of a Labour/Lib Dem coalition? Or should I vote Lib Dem on the theory that the more votes they win, the more likely it is that we’ll get the reforms we need, even if Cameron ends up in Downing Street?

Reader, for the first time in my life, I may not actually decide until I’m in the voting booth.