(REUTERS/Brian Frank)

Correction: An earlier version of this article mischaracterized Kent Talbert's comments to Wonkblog about the distinction between standards and curriculum. This version has been corrected.

In a lawsuit filed Wednesday, Louisiana Gov. Bobby Jindal claims that the Obama administration improperly impinged on local school administrators by encouraging states to adopt the Common Core standards.

The federal suit marks an escalation in a series of legal skirmishes in Louisiana and elsewhere over Common Core, the hotly debated effort to establish a more-or-less uniform national rubric for evaluating students' academic performance from kindergarten through high school. Jindal initially supported the program. The Republican governor's critics have accused him of pandering to tea-party conservatives around the country who oppose the standards and putting his presidential ambitions before students in Louisiana. Some dismissed his suit as lacking merit, saying that the administration gave states leeway to shun Common Core if they chose.

All the same, the governor's case raises anew an important question about the Common Core that divides its supporters and its detractors: whether the initiative is just a set of standards that specify what students should learn, or a curriculum that details how they should learn it.

The administration invited states to compete with one another for grants to improve their schools, which were funded through the 2009 fiscal stimulus in a program known as Race to the Top. One of the criteria the the administration said it would consider in reviewing states' applications was whether the state was adopting standards shared by other states.

Subscribing to Common Core was the most obvious way to satisfy this criterion. A coalition of state officials initiated Common Core, with support from the Bill and Melinda Gates Foundation among other sources.

The administration is also financially supporting the effort to write new tests for Common Core. Jindal will have to convince a court that these actions together constituted a mandate that states adopt a particular curriculum, which other laws prohibit the executive branch from imposing.

States, though, were free to apply to the Education Department for grants without adopting Common Core, although they would be less likely to receive them, or not to apply for the grants at all, argue defenders of the policy.

"To say this effectively nationalizes education curriculum, that’s just completely not true," said Michael Brickman, the national policy director at the conservative Thomas B. Fordham Institute.

What's more, Common Core broadly describes what students are supposed to be able to do after completing each grade, but it does not include reading lists, lesson plans or other details on how teachers are to help their students achieve those goals.

"It would be trivially easy for the lawyers representing the federal government to argue that the Common Core is not a curriculum," said the Brookings Institution's Russ Whitehurst. "It clearly has implications for curriculum, as any state standards would, but it is not a curriculum. It has none of the things that one would view typically as critical components of a curriculum."

Advocates respond that that school officials might be making poor decisions about what to assign students, but that they'd do so even without a set of national standards, and that testing on Common Core will at least help districts evaluate their curricula.

Kent Talbert, a former Bush administration lawyer whose 2012 white paper appears to have been a basis for Jindal's complaint, disagrees, saying that standards and curriculum are closely connected under the Obama administration's policy. Talbert and his collaborators argued that the administration knew that it would be seen as endorsing Common Core and that federal officials aimed to prod states not just to adopt the new standards, but also to reform their curricula.

"The standards and the assessments supported with federal money will in fact drive the curriculum," Talbert told me. "That’s supposed to be a purely local matter."

If the courts bought that argument, Obama could be forced to abandon many of his education policies, which rely on executive authority rather than specific legislation.

"It would be very radical to say that everything the Obama administration has been doing basically in terms of its reform agenda since it came into office is illegal," said Brookings's Whitehurst. "I can't see any jurist wanting to venture down that particular path."

At this point, though, it is hard to know what the practical effects of a ruling in Jindal's favor would be, since most states have adopted Common Core already (including Louisiana). Even if the administration were barred from offering rewards in the future for subscribing to the standards, it isn't clear whether states would decide to abandon them for that reason, undoing years of work on the part of administrators.

Common Core may be out of the courts' hands by now, but the debate over the fine line between standards and curriculum is sure to continue among politicians, teachers and parents.