FWIW, I don't disagree with the demographics either. The question is what the impact will be.
James Carville, the man who masterminded Bill Clinton's first election victory, has predicted the Democratic Party will dominate American politics for the next four decades due to "seismic shifts" in demographic voting patterns...
"There have been long periods where one party generally has the upper hand. You never win every election – the Democrats won't win every election – but for 40 years the underlying dynamics in demographics stay with them," he told the Daily Telegraph.
From 1896 to 1932 there was just one Democratic president and from 1932 to 1968 just one moderate Republican, Eisenhower. Since 1968 the Republicans have generally held sway, exploiting the backlash to the liberal society.
But in the first decades of the 21st century, young voters have swung heavily to the Democrats, a crucial advantage given that voting behaviour in the US is generally set when people are in their 20s.
Hispanics and blacks are growing as a percentage of the population, while white men and Christians, who have voted heavily Republican for the past 40 years, are declining.
"It's the kind of seismic shift we have never seen before," he said.
As an unashamedly partisan Democrat, Carville rejoices in Republican misfortune, but also claims that none of his high-powered Republican friends – Congressmen, pollsters and columnists – disagree with his hypothesis.
We already know that, as in the UK, on current trends US whites (in the UK, Native Brits - to distinguish them from the equally melanin-challenged Eastern Europeans) will become a minority. By 2042 Hispanics (who 'traditionally' vote Democrat) will be 30% of the popuation.
All parties change, but the Democratic Party may have to change more than most to accommodate its voters. It may not be the Democratic Party that Carville wants. Given that the idea of integration, of the melting pot, is no longer fashionable, it's likely to be a lot more like a Mexican political party than it used to be.
But wait ! I hear you say (or not) - what about the demographic differential between the Godly and the unGodly ? Republicans have more kids than Democrats, don't they ?
Yes they do. And white UK liberals have few children. But the scale of mass immigration in both countries is enough to wipe out the differentials. Not enough Labour voters having kids ? Import some more.
Unless you're hung up on political labels what's really important is the change to the parties over time, not what they're called. A Cameron Tory government would be far less socially conservative than Attlee's 1945 Labour Party, for example. My prediction FWIW is that US politics will be more like Mexican politics in thirty years, while UK politics will be more like the politics of the Indian subcontinent. There's also the probability in the UK that the tensions between the 70s types who now constitute our ruling elite, with their talk of 'retarded homophobes', and their pious and fecund Muslim voters, will lead to a split and the formation of a new party or parties.
"Traditionally Labour has been the party of immigrants, but a point will be reached at which they (Labour) are not needed any more and with a cry of 'so long and thanks for all the outreach workers' the Muslim vote will depart. The divorce will be messy."