A new poll shows that President Obama’s “historic achievement” is historically unpopular:

After remaining roughly evenly split for most of the last year and a half, this month’s tracking poll found more of the public expressing negative views towards the law. In October, about half (51%) say they have an unfavorable view of the Patient Protection and Affordable Care Act (ACA), while 34 percent have a favorable view, a low point in Kaiser polls since the law was passed. While Democrats continue to be substantially more supportive of the law than independents or Republicans, the change in favorability this month was driven by waning enthusiasm for the law among Democrats, among whom the share with a favorable view dropped from nearly two-thirds in September to just over half (52%) in October.

Americans are more than twice as likely this month to say the law won’t make much difference for them and their families as they are to say they’ll be better off under the law. Forty-four percent say health reform won’t make much difference to them personally, up from 34 percent in September. Meanwhile 18 percent say they and their families will be better off, down from 27 percent last month. (The share who thinks they’ll be worse off personally held steady at roughly three in ten, where it has been since the law passed in 2010.) Here, too, changes in views among Democrats helped shape the overall change.

Part of the problem for Obama is that his own party has grown disenchanted with the law:

While Democrats continue to be more likely to support the law compared with independents and Republicans, the uptick toward negative views this month was largely driven by a decline in enthusiasm among Democrats. For example, while about half (52 percent) of Democrats currently have a favorable view of the law, that share is down 13 percentage points from last month’s poll (65 percent).

This has profound implications for the 2012 election, for the future of health care and for the potential Supreme Court review of the law.

If ObamaCare is no longer much of a selling point with his own base, Obama going to have to dig for some “accomplishment” to tout. That’s been it, really, so far; If there’s not that much bang for the buck in raising it (and only 32 % of independents like ObamaCare), he will find it hard to use it offensively (Republicans want you to lose coverage!) or even defensively against Mitt Romney if he is the GOP nominee ( What’s the matter with ObamaCare — you passed most of it?)

Second, if Romney does get the nomination, he’d do well to sharpen his attack on the aspects of the statute that he did not adopt in his state — tax hikes, the Independent Patient Advisory Board (15 bureaucrats rationing care), the expansion of Medicaid, etc. The general unpopularity of the statute makes it that much easier for Romney to defend his own effort (RomneyCare is well regarded in his state) while attacking ObamaCare (voters don’t like it).

This also opens up the possibility after the 2012 election, if Republicans get the White House and pick up Senate seats, that there could be some bipartisan support for “repeal and replace.” This is critical, I think. As many conservatives argued with regard to passage of ObamaCare, a huge legislative innovation should have bipartisan support. If there is bipartisan support for dumping it, it may be possible to find bipartisan support for a substitute.

And finally, the Supreme Court is not supposed to look to public opinion. The justices would be aghast if a litigant argued, “Go and ahead and strike it down — people pretty much hate it anyway!” That said, the increasing unpopularity of the bill serves as some background noise, in this case perhaps the soothing white noise to calm justices’ qualms about invalidating Congress’s work.