The two most important parts of Obama’s legacy could be on the brink of collapse, and this time there's no back-up plan

You could conclude that for Barack Obama the last couple of days have been decent. Barely had the malodour of Benjamin Netanyahu’s Iran speech to Congress cleared on Tuesday than the latest attempt by Republicans to kill his order shielding five million illegal immigrants from deportation had collapsed.

For John Boehner, the House Speaker, they have gone less well. He was the guy who invited the Israeli leader to bellyache about the deal the US and its allies are trying to negotiate with Iran on nukes.

And it was his brainwave to try to force Mr Obama to abandon his immigration steps by threatening to withhold money from Homeland Security. Trading the nation’s security for political gain never looked smart.

If you want to look like the only grown-up in the room it helps to have foes like Mr Netanyahu and Mr Boehner.

But appearances can be deceiving. What two things above all others does Mr Obama see forging his legacy, beyond rescuing the economy? One would be achieving a landmark deal with Iran which one day may change the whole equation in the Middle East. The other is the long-term survival of the Affordable Care Act, ACA, known as Obamacare. Both, it turns out, are in significant peril.

The drama that was Tuesday on Capitol Hill had, by yesterday, shifted to the Supreme Court, where the nine justices sat in a line and listened to arguments in the latest challenge to the health law. The thrust of it sounds entirely disingenuous, as I’ll explain. But there is no reason to be confident it won’t work.

Underpinning Obamacare is a provision that allows the federal government to give generous subsidies to middle- and low-income Americans to buy insurance plans. The law says those subsidies are available through exchanges – or insurance marketplaces – that have been “established by the states”. Yet, the way it has happened only 13 states and the District of Columbia have set up their own exchanges. Everywhere else consumers use an exchange that the federal government put in place, with three of those working as state/federal hybrids.

You see the problem. The federal exchange wasn’t “established by the states”. Someone fouled up writing this puppy and the four plaintiffs, all from Virginia, hope to use that to finally drive a stake through it. The government argued yesterday that the rest of the law – it is over a thousand pages long – makes it clear what the intention of the law was: to make the subsidies available to everyone, never mind which exchange they are shopping in. But a legally literal reading may say the opposite.

No one knows how the Court will fall on this. If the Justices divide along ideological lines, the law’s in the soup. (Republican appointees outnumber Democrat appointees five to four.) If the subsidy system is eviscerated, the law as passed in 2010 is likely simply to fall apart.

More than half of the 10 million Americans who now have insurance thanks to the law will find their subsidies taken away. Many will abandon their policies; only the sickest will cling on to them. Premiums across the board will skyrocket.

On that the experts are agreed. The law would wither in a “death spiral”, according to America’s Health Insurance Plans, the country’s health insurance trade group.

“It would leave consumers in those states with a more unstable market and far higher costs,” it said in a brief to the Court.

Of course, the law could be fixed, but only if the Republicans in Congress choose to help. Right... as if they would.

Mr Obama said this week he feels confident the Court will see sense. But he also said he has no back-up plan if it doesn’t. “I’m not going to anticipate that,” he said in an interview with Reuters. “I’m not going to anticipate bad law.” He is screwing his eyes shut, it seems, and hoping for the best.

Maybe that’s wise, for his sanity, because this spring both planks of his legacy as president are in the balance.

The Supreme Court will announce its decision on Obamacare in June. Meanwhile there is every danger that the talks now going on in Geneva between the allies and Iran may come to naught.

Mr Netanyahu – who mustered his rhetorical best on Tuesday to potentially sabotage the Iran deal – and Mr Boehner – who has presided over 56 votes no less in the House to try to repeal Obamacare – may yet share the last laugh.