Granting Tom Maguire’s point that history begins and ends in The One’s mind with his own presidency, I think Obama’s right this time.

In a provocative argument designed to rescue his foundering health care plan, President Barack Obama will warn Senate Democrats in a White House meeting Tuesday that this is the “last chance” to pass comprehensive reform…

White House Communications Director Dan Pfeiffer told POLITICO: “If President Obama doesn’t pass health reform, it’s hard to imagine another president ever taking on this Herculean task. For those whose life’s work is reforming health care, this may be the last train leaving the station.”

Previewing the message, Vice President Joe Biden said on MSNBC’s “Morning Joe”: “If health care does not pass in this Congress … it’s going to be kicked back for a generation.”

Senate majorities may change but the graying of the population is a constant, which is why Karl’s correct that this will only get harder for the left in years ahead. As the Medicare rolls bloat with Boomers and medical advances extend lifespans, the you’re-not-sacrificing-my-benefits! demographic will be even bigger and fiercer at the polls than it is now. Thanks partly to ObamaCare, independents over age 55 already favor congressional Republicans over Democrats; if they’re not prepared to share the generational wealth and endure a little rationing now in the name of universal health care, their mood won’t be improved circa 2030. Especially since we’ll have long past the point of solvency for Medicare by then, leaving the program and its participants hungry for every last dollar they can scrounge from the budget.

So this is it for the Dems, unless they’re content to ease off and accept piecemeal centrist reforms (interstate competition for insurers?) over the next few years. And it looks like they’re going to make it, finally: Although Snowe reportedly told GOP leaders that she won’t be the 60th vote for cloture, Nelson’s being bullied into going along and Lieberman now sounds like a yes. No word from Lincoln, Pryor, or Bayh, but if Joementum doesn’t have the balls to kill this thing off singlehandedly, I can’t believe any of them will. In fact, irony of ironies, Lieberman may have ended up doing the left a favor. Says Jonathan Cohn at TNR:

Disappointed progressives may be wondering whether their efforts were a waste. They most decidedly were not. The campaign for the public option pushed the entire debate to the left–and, to use a military metaphor, it diverted enemy fire away from the rest of the bill. If Lieberman and his allies didn’t have the public option to attack, they would have tried to gut the subsidies, the exchanges, or some other key element. They would have hacked away at the bill, until it left more people uninsured and more people under-insured. The public option is the reason that didn’t happen.

Ramesh Ponnuru and Karl (again) made the same point months ago. Instead of attacking the bill at all its points of unpopularity, e.g., the individual mandate that dictates fines and even prison terms for people who refuse to buy insurance, the conservative assault has been drawn to the public option and its potential to metastasize into single-payer. A worthy battle, but winning it is still going to leave us with the basic outline of ObamaCare in all its eventual deficit-busting glory. Like Byron York says, no matter how bad the polls get, there’s only one way out for the Democrats at this point. Exit quotation: “[T]hey think they know what’s best for the public… They think the facts are being distorted and the public’s being told a story that is not entirely true, and that they are in Congress to be leaders. And they are going to make the decision because Goddammit, it’s good for the public.”