Additional reporting by Max Rivlin-Nadler and Gizelle Lugo.

UPDATE: The entire ACA has been upheld by the Supreme Court, with Chief Justice Roberts joining the majority. According to SCOTUSblog, “the entire ACA is upheld, with the exception that the federal government’s power to terminate states’ Medicaid funds is narrowly read.” The Court decided 5-4, with Kennedy dissenting and Roberts essentially saving the ACA, going against party lines.

The Nation’s David Cole parses the decision:

The law has long been that Congress can enact a tax for any purpose to further the general welfare. Unlike its regulatory powers, Congress can point to a specific power that they have for the ACA—the power to tax. Because the only consequence is that a person who doesn’t get insurance will be taxed, there’s no restriction on what Congress can do. The court upholds the mandate as an exercise of the taxing power.

Two things are remarkable about this decision. Everybody thought that Kennedy would be the decisive vote. If he went with the conservatives, then it would be struck down. If he went with the moderates, it would be upheld. The shock is that Chief Justice Roberts was the one who broke with the conservatives. The other remarkable thing about the ruling is that the conservative justices would have invalidated the entire law based on one provision, the individual mandate. It would have put us way back, well beyond square one.

You can’t let the perfect be the enemy of the good. This is a law that will expand healthcare insurance to millions of Americans who didn’t have it before. It’s not the best law, obviously. The question was, does Congress have the power to deal with a large social issue and regulate the industry and make citizens buy into a system that will help everyone? Thanks to Roberts, they can do this. If the ACA doesn’t end up helping people, then there can now be better reform in the future. People who think that it would be good if it was struck down and would make us closer to single-payer, is just ridiculous.

Kevin Russell over at SCOTUSBlog has a good analysis of the Court’s ruling on Medicaid expansion. The Court was deeply fractured on this question, with Ginsburg and Sotomayor seeking to uphold the expansion entirely; Roberts, Kagan and Breyer arguing that the federal government can’t strike all of a state’s funding under the Constitution; and the dissenters—Scalia, Kennedy, Thomas and Alito—backing the chief justice. This would have struck down the entire expansion, so Sotomayor and Ginsburg voted with the plurality. The impact of the ruling decision, as Russell puts it, is as follows:

The Court’s decision on the constitutionality of the Medicaid expansion is divided and complicated. The bottom line is that: (1) Congress acted constitutionally in offering states funds to expand coverage to millions of new individuals; (2) So states can agree to expand coverage in exchange for those new funds; (3) If the state accepts the expansion funds, it must obey by the new rules and expand coverage; (4) but a state can refuse to participate in the expansion without losing all of its Medicaid funds; instead the state will have the option of continue the its current, unexpanded plan as is.

* * *

With the Supreme Court set to issue—at long last!—its decision in the challenge to the Affordable Care Act, the entire political world is on pins and needles. At around 10 am tomorrow, a million twitchy fingers will be hitting refresh-refresh-refresh on Scotusblog (they’ve even set up a back-up site in case of a crash, scotusblog.wpengine.com). Pundits and legal scholars are reading the tea leaves of this week’s other decisions and the oral arguments made in March. Traders are placing bets. And political scientists are pushing their models into overdrive.

We’ll do our best here to link to interesting predictions, commentary and analysis of the decision when it comes down—so check back frequently as we’ll keep updating this post. (Also, tell us what you think will happen and how the decision will affect you in the comments thread. We’ll repost some of those in this blog.) TheNation.com will also host Democracy Now!’s livestream of the decision, which starts at 10 am, featuring our legal affairs correspondent David Cole. Health insurance industry whistleblower Wendell Potter will also weigh in with his analysis of the decision and what it means for meaningful reform. And of course, they’ll be smart, progressive takes on the ruling, what it means, what it doesn’t and what to do next from bloggers like George Zornick, John Nichols, Ilyse Hogue, Ari Berman and Ben Adler.

But before we recap some of what some prognosticators are prognosticating, it’s a good time to remember what’s at stake. Almost 50 million Americans lack health insurance. Millions of people with pre-existing conditions are priced out of the market, and thousands die each year because they can’t get the care they need. In 2011, $2.7 trillion was spent on healthcare in the United States, more than any other nation as a percentage of GDP. These costs that are rising each year at an unsustainable rate and could reach 20 percent of the US economy by 2021.

The Affordable Care Act doesn’t fix all of this—but it does lower costs through industry reforms, creates state exchanges, extends Medicaid coverage to millions and requires insurance companies to cover those with pre-existing conditions and people under 26 on their parent’s plan (as former Nation intern Zoë Carpenter points out, that’s already given over 6 million young Americans access to health insurance). All told, about 30 million people would get coverage through the ACA’s provisions, about half of them through the state exchanges that are set to launch in 2014. The individual mandate, of course, is the cornerstone of those exchanges. Most likely, that’s what’s at stake tomorrow, but the Court could strike down the whole bill. Or uphold the whole bill. Or variations in the middle. As Jonathan Chait reports at New York, there are five different likely scenarios:

1. Leave it all in place.

2. Technically eliminate the mandate to buy healthcare while leaving in place the fine for not having health insurance. (Essentially upholding the fine as a tax while technically eliminating the requirement.)

3. Eliminate the mandate, and the fine, but leave in place the regulations that insurance companies not discriminate against people with health risks and the subsidies for buying insurance.

4. Eliminate the mandate, the fine, insurance regulations, and the subsidies.

5. Nuke the entire law.

Jonathan Cohn over at TNR also has a great primer on the Obamacare decision with similar scenarios. He’s also eloquently laid out what’s at stake for as many as 100 million Americans. Both Cohn and Chait think that the ACA could still function if the mandate is struck down, depending on what other elements of the bill remain, especially if the penalties and subsidies remain in place. That scenario would be a “moral victory” for conservative critics, says Cohn, but not much damage to the law itself. And last week George Zornick reported that, since a vast majority of Americans want some kind of healthcare reform, there are still options on the table, even with a bad decision. Like passing single-payer, to start, but also state-level mandates, penalties and more generous subsidies.

Also at stake in the decision is the legitimacy of the Supreme Court itself (see Barry Friedman in The Nation on the subject). As this week’s lead editorial, “A Supreme Court for the 1 Percent,” points out, with its decision in Citizens United and its refusal to reconsider that decision last week, the right-wing majority on the Court has “already guaranteed that insurance companies and other corporations will continue to have dramatically more say in American politics than citizens.” More than 75 percent of all Americans think that the Court’s justices make decisions based on their political views rather than legal analysis. And if the broccoli thesis—straight from right-wing talking points—essentially wins the day tomorrow, well, 75 percent of Americans would be right.

Now, onto some folks bold enough to predict what will happen tomorrow:

The Daily Beast’s Michael Tomasky predicts that the mandate will be overturned 5-4. In taking the most cynical view, Tomasky believes the judges will make a political decision and try to inflict as much damage on Barack Obama and the Democratic Party as possible. The other parts of the law will remain intact, trying to limit backlash against the Court and the possibility of riling up the Democratic base. He writes:

They’ll want to minimize backlash, in other words—both backlash against them as an institution and electoral backlash that might help Obama and the D’s. So they’ll limit their overturning to the mandate. And as I say, the majority opinion will say things like gee, we are deeply sympathetic to the problems inherent in the health-care system, but regretfully, we simply can’t endorse this method under our reading of the Constitution.

That way, Obama is screwed (yes—the D’s and even maybe the media will try to paint that as a partial win for the White House, but it won’t be in my view). And yet the majority also seems reasonable. That’s the needle I predict they’re going to thread. What about the law, you say? Fiddle dee dee. This is politics, pure and simple.

The only hope that Tomasky holds out is that it’s possible the justices will take the same view they took with the SB 1070 decision a few days ago (when they said they had no idea how “show your papers” was going to be enforced, so they could not rule on it), and will opt to wait and see how the individual mandate is implemented. He doubts it, though. [MR-N]

Ed Whelan at National Review also has the Court striking down the individual mandate by a 5-4 vote. But his reasoning is, for lack of a better term—weird.

He writes that it’s a SCOTUS tradition for a justice to read only a single dissenting opinion from the bench each term. As Scalia read the dissent for the SB 1070 ruling earlier this week, and didn’t save his turn for the healthcare ruling, it means that he will most likely be in the majority tomorrow. The problem is, the whole piece is now prefaced by an update that points out that Scalia already read a dissenting opinion back in March. So now he’s read two—invalidating Whelan’s argument. Or maybe just showing how unrealistic it is that he would go on to read a third. Either way, a lot of tea leaves here, not much actual analysis. [MR-N]

Walter Dellinger at Slate doesn’t believe the Court will let a major reform be struck down on such a divided bench. If they do invalidate the individual mandate (possibly unraveling the rest of the law in the process), they would then “own the resulting healthcare system for the next decade and beyond.” He continues, “It’s a slightly highbrow version of the universal rule: ‘You broke it, you bought it.’”

The middle ground he finds is that the Court might give a “theoretical victory” to conservatives, but essentially leave the law, including the mandate, in place through a rhetorical compromise. He writes:

Here is where the Court could give a theoretical victory to the challengers: By saying that if you did read the law that way—as its text seems to suggest—as making lawbreakers out of those who don’t acquire health insurance, it would be unconstitutional. But we don’t read it that way, the Court could say. We read it as nothing more than an incentive to purchase coverage. No one is compelled to make a purchase from a private party because they can choose, instead, to pay a relatively modest penalty that never exceeds 2.5 percent. This makes the decision about whether or not to have insurance a genuine choice, not a compulsion.

That’s some nifty reasoning, but are Justices Kennedy or Roberts up for it? [MR-N]

Here’s Senator Ben Nelson’s take on the outcome of SCOTUS’s decision as reported by Brian Beutler for Talking Points Memo. Nelson warns that if SCOTUS strikes down the Affordable Healthcare Act, the decision will lead the nation down a path towards a single-payer system. Nelson, who recently announced his retirement and is considered to be “the most conservative Democratic senator,” is an “unlikely champion” of the law, according to Beutler. An initial skeptic of the Dems’ approach towards healthcare, Nelson was one of the last holdouts on the vote for the ACA. But while the senator seems to have changed his tune and is not a fan of either single-payer or returning to the status quo, Beutler anticipates Nelson warming up to the former outcome should that eventuality occur. [GL]

The Guardian surveys a panel of law experts for their predictions—and the majority of them think the law will be upheld.

Timothy Jost, a law professor at Washington and Lee University thinks, “when they [SCOTUS] consider seriously the expansive deference they have accorded Congress in their prior decisions, they will uphold the law in full.” In other words, if they limit Congress on this legislation, how badly would they contradict their previous rulings?

Martha Davis, constitutional law professor at Northeastern University, sees 6-3 for upholding, with an 8-1 court also approving of the Medicare expansion.

Michael Sparer, professor health policy and management at Columbia University, also predicts a 6-3 vote. “Why? Because it is the right decision on the law (says the still-naive optimist). And because once Kennedy decides to vote to uphold the law, Roberts will join—both to make the decision seem less political, and also to ensure that he can write the majority opinion.”

Thomas M. Keck, a professor constitutional law and politics at Syracuse University, also goes with 6-3. “In doing so, the decisive justices will suggest that a straightforward government mandate that all individuals purchase health insurance would be unconstitutional, but that the ACA’s mere imposition of a tax penalty on individuals who fail to obtain health insurance is constitutionally legitimate.”

A lone voice on the panel thinks the law will be struck down—possibly in its entirety. Scott Lemieux, professor of political science at the College of Saint Rose, “I’d say the Court will vote 5-4 to strike the mandate, and they will rule that it cannot be severed from at least some of the other provisions in the act.”

The optimism of the law professors points out the almost certain constitutionality of the legislation. But will the decision be made based on the rule of law or politics? [MR-N]

Last minute updates [10 am]:

Think Progress has a simple rundown of all the things Americans would miss out on if the law is struck down.

If you’re just joining the coverage, and still don’t know exactly what the ACA is all about, The Kaiser Family Foundation has put together a video explaining exactly what it does, and who it helps.

Also, Michele Bachmann will be in the building, looking like she just scored front-row tickets to a John Mellencamp show.