Critics of the Supreme Court -- liberal and conservative -- often say the court should leave more room for elected bodies and the voters to decide important issues. That's exactly what the U.S. Supreme Court did when it upheld the Affordable Care Act last week.

• First, the court leaves it up to the voters in November whether they want to re-elect President Barack Obama and keep the law or elect Mitt Romney and a Republican Congress to try to repeal it.
• Second, by leaving it up to the states whether to agree to the big expansion of Medicaid provided by the law, the court allows elected state officials to decide whether to shun a big pot of federal money to pay for the medical care of hundreds of thousands of its poorest citizens.
• And, third, the court made it harder for Congress to impose mandates on people because it may have to call them taxes.

The court put limits on three of Congress' deepest wells of power -- the Commerce Clause, the spending power and the Necessary and Proper clause.  But it left the door open to mandates, such as the health-care mandate, enacted under the taxing power.

That may make it harder for Congress to impose mandates because taxes are less popular with voters than mandates justified in other ways. Most political observers doubt that the ACA would have passed if it had been called a tax.

In the near term, the biggest impact will be on the presidential race and on the fight ahead on whether states that challenged the law, like Missouri, will take the Medicaid dollars.

This is an issue that threatens to split along red-state, blue-state dividing lines.

The Medicaid expansion of health coverage to those making up to 133 percent of poverty was intended to provide health care to an additional 17 million Americans. This expansion of coverage is about half of the expansion projected by the entire law.

Democratically controlled states that did not challenge the law will undoubtedly go ahead with expanding Medicaid coverage to a large group of their citizens who now don't have health care.

If Republican-controlled states do not expand, they will be in a bind. Their own citizens will be paying the federal taxes to fund the expansion in Democratic states, while their own poor are not getting the benefits.

The hardest burden will fall on families who earn below 100 percent of poverty and are not now covered by Medicaid in their states. This group will not be eligible for the tax credits or subsidies to buy health insurance. Those making from 100 to 133 percent of poverty will qualify for the credits and subsidies.

Sidney Watson, a health law expert at Saint Louis University, put it this way in an email. "The now voluntary Medicaid expansion for children and adults up to 133 percent is critical. It is possible that some states will not voluntarily expand Medicaid and we will end up with the poorest left out. As a result of the Supreme Court's decision, we now have health reform that creates an interesting federalism issue -- the states are the final decision-makers on whether the very poorest have access to affordable health insurance.

"Medicaid is the only option for those with incomes under 100 percent federal poverty line. With Justice (John) Roberts' decision, states can choose not to cover these children and adults, but will not be at risk of losing their federal Medicaid match for their other groups of eligibles. They do remain eligible for a very attractive federal 100 percent match for 2014-2016 with a phase down to a very generous 90 percent. This will make for very interesting politics if states, like Missouri turn their back on the poorest with such a generous offer of federal help."

Watson added that "it is important for supporters of the law to claim victory for the court deciding 5-4 to allow the expansion to go ahead and to use 'severability' to strike the requirement that coverage be mandatory on the states." In other words, a severability clause allowed the expansion to go forward without the threat on states of losing old Medicaid money.

"Remember," wrote Watson, "there were seven votes that the Medicaid expansion as a mandatory expansion was coercive and it could have been struck completely, not leaving states with the option to cover this new group of children and adults. This half loaf is good."

Watson is able to take a measure of satisfaction in this result because she was one of a group of law professors who pointed out to the court that they could use the severability option to allow the expansion to go ahead.