Harvard professor Laurence Tribe, who taught both President Obama and Chief Justice John Roberts at Harvard, wrote on SCOTUS Blog: “Today, Chief Justice John Roberts delivered a heroic rebuke to the growing number of Americans who feared the Supreme Court had lost the ability to rise above the narrowminded partisanship that dominates the country’s political discourse.

“More than a year ago, writing in the Boston Globe, I made a simple point … that ‘this law doesn’t literally force anybody to do anything; it just increases the tax liability of those who refuse to buy insurance.’ Fortunately, the Chief Justice ended up articulating essentially the same common sense view despite protestations and pressure from his conservative colleagues on the Court that he approach the case more artificially.”

Dana Milbank with the headline of the day: “The umpire strikes back.” His lead: “John Roberts was the first justice to appear from behind the curtains when the buzzer sounded in the Supreme Court chamber at 10 a.m. sharp. He forced a tight grin and scanned the audience, which, on this historic day, included several members of Congress and retired Justice John Paul Stevens. The only hint of what was afoot came from Justice Antonin Scalia, who, taking his place at the chief justice’s right, bowed his head as if in mourning… In the audience, Sen. Orrin Hatch (R-Utah), an opponent of the law, folded his arms across his chest, his mouth slightly agape. Sen. John Barrasso (R-Wyo.) put his chin in his hand. Rep. Tom Price (R-Ga.), a leader of House conservatives, shook his head. Scalia was reclining in his chair, staring blankly. Justice Clarence Thomas was practically horizontal.”

And: “Whatever one thinks of the health-care ruling, Roberts’s opinion was extraordinarily brave.”

National Review didn’t think it was brave, but a “folly” instead: “If the law has been rendered less constitutionally obnoxious, the Court has rendered itself more so. Chief Justice Roberts cannot justly take pride in this legacy… Opponents should take heart: The law remains unpopular. Let the president and his partisans ring their bells today, and let us work to make sure that they are wringing their hands come November.”

Charles Krauthammer calls this decision by Roberts his “Nixon-to-China” moment. “Why did he do it? Because he carries two identities. Jurisprudentially, he is a constitutional conservative. Institutionally, he is chief justice and sees himself as uniquely entrusted with the custodianship of the court’s legitimacy, reputation and stature. … As a conservative, he is as appalled as his conservative colleagues by the administration’s central argument that Obamacare’s individual mandate is a proper exercise of its authority to regulate commerce. … But he lives in uneasy coexistence with Roberts, custodian of the court, acutely aware that the judiciary’s arrogation of power has eroded the esteem in which it was once held.”

In fairness, as one of us will write later this morning, the taxing power argument didn’t come out of nowhere. Solicitor General Donald Verrilli argued strongly for it. For example: “If there is any doubt about that under the Commerce Clause, then I urge this Court to uphold  the minimum coverage provision as an exercise of the taxing power.”

Verrilli fended off eight justices, including the liberals, who came after him for the president and members of Congress denying that it was a tax. He argued that not all members of Congress denied it was valid under the Congress’ taxing authority, including Sen. Max Baucus (D-MT), who was entrusted as one of the key shepherds of the bill. And Verrilli acknowledged the legislative politics, but pointed out the reality: They might have thought, Your Honor, that calling it a penalty as they did would make it more effective in accomplishing its objectives. But it is in the Internal Revenue Code, it is collected by the IRS on April 15th.” 

Republicans want move toward repealing the law. House Majority Leader Eric Cantor (R-VA) on MSNBC’s Morning Joe this morning unabashedly called for the Senate, assuming a narrow GOP takeover of the Upper Chamber, to use “reconciliation” to kill the law.

But David Frum calls GOP hopes of repealing the law a “fantasy” and the ruling a “Waterloo.” “First, today's Supreme Court decision will make it a lot harder to elect Mitt Romney. President Obama has just been handed a fearsome election weapon. 2012 is no longer exclusively a referendum on the president's economic management. 2012 is now also a referendum on Mitt Romney's healthcare plans.”

He also notes that Republicans will be the ones faced with political backlash. “[I]t will be their town halls filled with outraged senior citizens whose benefits are threatened; their incumbencies that will be threatened.” And that since many Republicans want to keep elements of the bill, that one-page repeal bill “will begin to grow.” He adds that there’s “no internal consensus on what a replacement would look like. Worse, any replacement of the law's popular elements will require financing. But where is that money to come from?” And he contends the bill will become not just more popular, but more difficult to undo as states begin to implement it in 2014.

In other words: “If replacement does not happen in the first 100 days, it won't happen at all—that is, it won't happen as a single measure, but rather will take the form of dozens of small incremental changes adopted episodically over the next 20 years. The outlook then: Even if Republicans win big in 2012, they will have to fight inch by bloody inch for changes they could have had for the asking in 2010. Truly, this is Waterloo—a Waterloo brought about by a dangerous combination of ideological frenzy, poor risk calculation, and a self-annihilating indifference to the real work of government.”

On the other side of the aisle…

Huffington Post’s Stein and Grim: “Democrats won [yesterday’s] battle, but the war over health care remains unsettled… Having endured years of sustained attack for constructing a bill that was based, fundamentally, on conservative principles, Democrats on Thursday were conceiving of ways to make the Affordable Care Act more popular rather than structurally different.” And: “[A] bill that has been sold to the public before would need to be presented once again during the presidential campaign.”

Josh Marshall at left-leaning Talking Points Memo: “In politics like in everything else, wins tend to generate more wins. They excite the winners and demoralize the losers, especially when the losers were certain they were about to win big. Getting the wind knocked out of you and desperately choking for breath for a minute on the field isn’t a plus. So a loss for the opponents of ‘Obamacare’ strikes me as what it is: a loss for the opponents of ‘Obamacare.’ On all levels.”

Matt Yglesias on what’s at stake in November: “[I]t turns out that the provisions a Romney administration would need to repeal to gut the law are wildly popular. According to a Reuters poll earlier this week, 78 percent of self-identified Republicans favor ‘banning insurance companies from denying coverage for pre-existing conditions’ and 86 percent of them support ‘banning insurance companies from canceling policies because a person becomes ill.’

“In other words, once the basic framework of the law is in place, it’ll be all but impossible to kill. That’s probably why no country that’s instituted a universal health insurance program has ever rolled it back—even strong conservatives like Margaret Thatcher in the United Kingdom or the current right-wing government in Canada leave existing programs in place. The problem for Democrats is that if Romney takes office in 2013, none of this stuff will have actually happened yet. Repealing the law in its abstract form is a bit politically risky for Republicans but not nearly as risky as it will become in the future.”