Susan Collins jumped overboard weeks ago and our old pal Lisa Murkowski sounded today like she’s headed for the lifeboats, so Scotty B’s vote was a fait accompli.

Between all of that and Gingrich’s comments last week, the Democrats’ attack-ad brain trust must be having trouble keeping up with all the new material lately.

While I applaud Ryan for getting the conversation started, I cannot support his specific plan — and therefore will vote “no” on his budget…

First, I fear that as health inflation rises, the cost of private plans will outgrow the government premium support— and the elderly will be forced to pay ever higher deductibles and co-pays. Protecting those who have been counting on the current system their entire adult lives should be the key principle of reform.

Second, Medicare has already taken significant cuts to help pay for Obama’s health care plan. The president and Congress cut a half trillion dollars to the private side of Medicare — meaning seniors are at risk of losing their Medicare Advantage coverage.

Another key principle is that seniors should not have to bear a disproportionate burden. But that doesn’t mean we do nothing. If Medicare is to survive for current beneficiaries and future generations, we must act. The sooner Congress addresses this, the less painful it is likely to be — but more difficult adjustments will be required if we delay.

Brown’s own preference for fixing Medicare? Why, reducing “waste, fraud, and abuse,” of course, a prescription so tediously familiar and so unequal to the task of restoring solvency to the program that William Jacobson of Legal Insurrection is bidding him a not-so-fond adieu because of it. But then, this isn’t a vote being cast on policy grounds; this is a guy who’s up for reelection in the bluest of blue states and not ready to risk his own career on a budget that, alas, has no hope of passing the Senate even with his backing.

How many more GOP defectors will there be? Based on the party’s own alleged internal polling, there’s no telling:

It might be a political time bomb — that’s what GOP pollsters warned as House Republicans prepared for the April 15 vote on Rep. Paul Ryan’s proposed budget, with its plan to dramatically remake Medicare.

No matter how favorably pollsters with the Tarrance Group or other firms spun the bill in their pitch — casting it as the only path to saving the beloved health entitlement for seniors — the Ryan budget’s approval rating barely budged above the high 30s or its disapproval below 50 percent, according to a Republican operative familiar with the presentation…

“The tea party itch has definitely not been scratched, so the voices who were saying, ‘Let’s do this in a way that’s politically survivable,’ got drowned out by a kind of panic,” a top GOP consultant involved in the debate said, on condition of anonymity.

“The feeling among leadership was, we have to be true to the people who put us here. We don’t know what to do, but it has to be bold.”

Another GOP insider involved to the process was more morbid: “Jumping off a bridge is bold, too.”

Not all of the polls about Ryan’s budget are that dismal — remember this one? — but public opinion will undoubtedly be, shall we say, in flux during the coming 18-month Democratic Mediscare campaign. Pawlenty, in fact, has said he’ll introduce his own Medicare plan rather than sign on to Ryan’s. Which makes me wonder (and I say this as a Ryan fan myself): Given the potential, at least, for a huge backlash at the polls, why do the “Ryan 2012” advocates want to double down by making him the nominee? Eric Cantor floated that idea just today, and of course Bill Kristol’s a big fan too. I see the logic of it insofar as Ryan is smart, personable, soft-spoken, and judging by the reaction at his townhalls, a guy who’s perhaps uniquely capable of dropping a fiscal truthbomb on Americans without them taking up torches and pitchforks. (I wouldn’t mind seeing how Christie would sell his plan, though.) But then I look at that boldface part in the blockquote and wonder how far logic, even when expertly delivered, can really go, especially with Democrats screeching about the entitlement End Times from the sidelines. Even when the pollsters presented Ryan’s plan as the only plan capable of saving Medicare, people … still didn’t want to reform Medicare? That’s simply insane — and yet somehow not surprising. How do you run a presidential campaign when you have that degree of obstinate opposition stacked against you?

I can also understand a “Ryan 2012” movement from the standpoint of forcing the issue of entitlement reform in the most dramatic way possible, by nominating the guy who’s now the public face of the idea. Even if it backfires and we’re destroyed at the polls, we’re at least guaranteed laser-like national attention on this issue for more than a year, which in turn hopefully will force Democrats to take it up in 2013. They can do the entitlement math too; they know they’d either have to reform Medicare themselves once they’re back in power or The One will finally have to break the news to middle-class Americans that, no indeed, “the rich” can’t pay for everything after all. I’m guessing that the reaction to me saying that will be that it’s a crazy idea, that we can never trust the Democrats to reform entitlements, and that we’d be courting catastrophe by ceding this election to them in the name of taking a bold stand on principle. Fair enough, but then that brings us back to my question: Since no one knows what the polls on Ryan’s budget will look like after 18 months of Democratic demagoguery, why would you want to risk having him on the ticket? As I say, I can see the arguments, but it’s an even bigger gamble than Pawlenty’s ethanol gambit in Iowa today. (Much bigger!)