You forget how young the architects of Labour's extraordinary victory were. Tony Blair became Prime Minister a few days before his 44th birthday. Alastair Campbell was about to turn 40. Exhausted, they stumbled into Downing Street on the morning of May 2nd, with an unassailable majority behind them.
They campaigned as if the election was on a knife-edge, perpetually terrified they might just screw it up, and lead Labour to a fifth successive defeat. In reality, Blair's victory was largely assured from the moment he became leader in 1994.
It almost didn't matter what the party promised -- in fact it promised almost nothing in a slim manifesto, built around a pledge to stick to tough Conservative spending limits.
Five years earlier, many voters had been looking for change, but they could never be convinced Neil Kinnock had the skills to be Prime Minister. A change of Tory leader proved enough.
But the party ran out of steam a few months later, stumbling into economic crisis, falling apart over Europe. All Labour had to do was look competent.
On the night of May 1st the country's future leaders watched, somewhat amazed, as dozens of Conservative seats fell, in places assumed to be beyond Labour's reach. The Tories lost 178 seats that night, and Labour finished on 418 -- a majority of 179. The party won 13.5-million votes.
Landslides bring their own problems. Dozens of people who never expected to be MPs suddenly find themselves in the Commons, with little political experience, and now with little to do other than vote. Individual backbenchers become lobby fodder, and it can be a relatively boring life.
Feeling neglected, they can get restless, and some will turn against their own party, like attention-seeking toddlers. Resentments fester, grudges grow, and eventually erupt in public.
Landslides can also make leaders arrogant. Labour moved carefully in its early years in power, but after winning a near-identical landslide in 2001, started to grow in confidence. Two years later, a huge majority, and support from the Conservative opposition, meant warnings about the Iraq war were ignored.
It's hard to be hated
Tony Blair now says he finds it hard to be hated by so many people. In particular, by so many inside the Labour movement. From the outside, it's extraordinary to watch the party disown its greatest electoral triumph.
You'd imagine Jeremy Corbyn would welcome the introduction of a minimum wage and civil partnerships, a tax rise to boost NHS funding, devolution to Scotland, Wales and London, and in tax credits a huge redistribution of wealth.
But Labour's current leader sees all that through the prism of Iraq, and for him it poisons policies he would otherwise readily have advocated.
Rather than celebrating the 20th anniversary of his party being swept into power, Mr Corbyn sees it as a cause for apology. Hatred of the Blairite project overwhelms rational analysis of Labour's governing legacy.
For many, both inside and outside Labour, the war in Iraq remains an unforgivable sin. And Labour stands accused of other significant mistakes too. The party never engaged in a serious debate on immigration, and its effects, and never sought to tackle angry myths about Europe -- arguably creating the conditions that would lead to the Brexit vote.
While Gordon Brown's government moved quickly to confront the effects of a global financial crisis, as Chancellor he did little to reign in the casino economics that set the stage for that crisis.
Twenty years on, the roles are reversed. The Conservatives look to be cruising to a comfortable election victory, Labour prepare for humiliating defeat. But no party dominates forever.
The Conservatives were reduced to just 165 seats in 1997, even though they won 300,000 more votes than Labour managed in 2015. By 2003, after another election defeat and Iain Duncan Smith's abysmal leadership, it seemed the party would never recover. But seven years later it returned to government, and today is dominant.
There's always a route back to power. But first, parties have to want to change if they're to win back lost voters. Right now, it seems Labour wants the voters to change instead.