They involve health care and same-sex marriage.
A question at the heart of these disparate cases is that of national uniformity: does the United States keep moving all 50 states toward universal health care, and toward same-sex marriage?
Or will the country be splintered into a red-state, blue-state scenario where the liberal parts of the country keep their federal health reforms and same-sex marriage while conservative places move the other way?
The Supreme Court decisions could come as early as Thursday.
One case involves whether to legalize same-sex marriage across the country, by forcing non-gay-marriage states to perform such weddings or recognize licences granted elsewhere.
The public-policy implications of the health-care debate are even more complex. Politicians are already grappling with what to do should the King vs. Burwell case gut President Barack Obama's signature health-care law.
Insurance exchanges could collapse in the two-thirds of U.S. states, depending on the ruling. Obamacare opponents want to end federal support for the exchanges in those states that didn't set up their own.
Health Secretary Sylvia Burwell explained how such a ruling could result in 6.4 million people losing their health coverage.
''(Without that federal subsidy) their premium cost goes up. When that happens, it is probable that they can no longer afford (insurance),'' she said.
''What happens is sometimes referred to as a death spiral (for an insurance program). In the individual market, previously prices were extremely high because only the sickest would go in.''
The U.S. has never had universal health coverage, and still doesn't.
But under the so-called Obamacare reform, everyone is entitled to get insurance under a system where the federal government pushes young, healthy people to buy it under threat of fines, while subsidizing the rest.
The Urban Institute estimates that in the states where there's a federally run exchange, 18.7 per cent of non-elderly residents had lacked insurance without the Obama reform. That figure has been pushed down to 10.5 per cent. And, it estimates, the number would bounce back to 15.1 per cent if the court weakens Obamacare.
The Republican-dominated Congress would then have to decide whether to rescue people's health plans — and therefore pass a new version of the Obamacare law they so emphatically detest.
The top Republican in the House said this week he'd like to do the former, but not the latter.
''Well, clearly, we're interested in protecting those millions of Americans who could lose their subsidies,'' John Boehner said. ''We are not interested in protecting a fundamentally broken law.''
It's not clear how he'd do one, but not the other.
The fallout could resemble the void left after landmark court decisions on political financing and voter ID — only this time it affects people's health care.
The conservative-leaning court has struck down those laws on constitutional grounds, and urged politicians to update them. In a deeply polarized Congress, those fixes never came.
One analyst, Elizabeth Wydra of the Constitutional Accountability Center, said during a Washington gathering last week that the court is moving the country in a conservative direction, by scrapping laws and claiming to want to let politicians fix them.
But other speakers at the same event defended the court. One used a colourful metaphor involving the destructive power of gravity.
The former assistant U.S. attorney general said it's fair to expect Chief Justice John Roberts to make constitutionally sound decisions, not solve problems for the other branches of government, like political paralysis.
"It's fair for him to look to other branches to solve their own problems," Viet Dinh told the panel event, organized by Politico.
"And if they can't do that, it's all he can do as a judge is to watch the bus go down the cliff."Suggest a correction