LinkMr Frum argues that just as America is changing, so the Republican Party must adapt its economic message and find more to say about healthcare and the environment if it is to survive.
He said: "I don't know that there's a lot of realism in the Republican Party. We have an economic message that is largely irrelevant to most people.
"Cutting personal tax rates is not the answer to everything. The Bush years were largely prosperous but while national income was up the numbers for most individuals were not. Republicans find that a hard fact to process."
Other Republicans have jumped ship completely. Ken Adelman, a Pentagon adviser on the Iraq war, Matthew Dowd, who was Mr Bush's chief re-election strategist, and Scott McClellan, Mr Bush's former press secretary, have all endorsed Mr Obama.
As I posted a few weeks ago, the true fiscal conservatives of the GOP need to abandon ship, and it looks like some are doing just that.
But the real bile has been saved for those conservatives who have balked at the selection of Sarah Palin.
In addition to Mr Frum, who thinks her not ready to be president, Peggy Noonan, Ronald Reagan's greatest speechwriter and a columnist with the Wall Street Journal, condemned Mr McCain's running mate as a "symptom and expression of a new vulgarisation of American politics." Conservative columnist David Brooks called her a "fatal cancer to the Republican Party".
The backlash that ensued last week revealed the fault lines of the coming civil war.
Rush Limbaugh, the doyen of right wing talk radio hosts, denounced Noonan, Brooks and Frum. Neconservative writer Charles Krauthammer condemned "the rush of wet-fingered conservatives leaping to Barack Obama", while fellow columnist Tony Blankley said that instead of collaborating in heralding Mr Obama's arrival they should be fighting "in a struggle to the political death for the soul of the country".
During the primaries the Democratic Party was bitterly divided between Barack Obama's "latte liberals" and Hillary Clinton's heartland supporters, but now the same cultural division threatens to tear the Republican Party apart.
Jim Nuzzo, a White House aide to the first President Bush, dismissed Mrs Palin's critics as "cocktail party conservatives" who "give aid and comfort to the enemy".
He told The Sunday Telegraph: "There's going to be a bloodbath. A lot of people are going to be excommunicated. David Brooks and David Frum and Peggy Noonan are dead people in the Republican Party. The litmus test will be: where did you stand on Palin?"
It's sad that it took somebody like Sarah Palin to finally bring to light how much of the socially conservative ideology of the GOP's base that fiscal conservatives would have to accept as part of their own party-wide ideology if they are to remain in the GOP.
Mr Frum thinks that Mrs Palin's brand of cultural conservatism appeals only to a dwindling number of voters.
He said: "She emerges from this election as the probable frontrunner for the 2012 nomination. Her supporters vastly outnumber her critics. But it will be extremely difficult for her to win the presidency."
Mr Nuzzo, who believes this election is not a re-run of the 1980 Reagan revolution but of 1976, when an ageing Gerald Ford lost a close contest and then ceded the leadership of the Republican Party to Mr Reagan.
He said: "Win or lose, there is a ready made conservative candidate waiting in the wings. Sarah Palin is not the new Iain Duncan Smith, she is the new Ronald Reagan." On the accuracy of that judgment, perhaps, rests the future of the Republican Party.
If Palin is the future of the Republican Party, I can't imagine that the "cocktail party conservatives" will stick around. Unless they want to join the Democratic party on a permanent basis, they're going to have to form their own "Bull Moose" party. I can only hope that it's the newly-formed party that survives this time around. It's so sad to see the party founded on anti-slavery principles with Abraham Lincoln as its first presidential representative become co-opted by religious fanatics that want a bimbo like Palin as the new face of the party. Ole Abe must be rolling in his grave.
