Jeb Bush, former governor of Florida, waves to the crowd during a keynote session at the National Automobile Dealer Association (NADA) conference in San Francisco, California, U.S., on Friday, Jan. 23, 2015. Bush is one of a large group of seemingly viable candidates for the presidential election, all of whom have conventional qualifications and fit within the Republican mainstream on public policy. Photographer: David Paul Morris/Bloomberg *** Local Caption *** Jeb Bush

A pro/con common core debate on FOX News Sunday over the weekend provides an early glimpse of a major 2016 GOP fault-line.

Arguing for the education standards was former Education Secretary Bill Bennett. Arguing against, Texas Governor Greg Abbott. Here's their exchange:

"A whole mythology has built up around common core.  Common core are state standards for math and reading by grade.  That's all they are," Bennett said. "Anybody who questions what the standards are should read what they are."

Abbott countered that states and governors have "buyer's remorse" even though they initially backed common core before it was implemented. "What we are dealing with is a one size fit all national standard being pushed down from the top by the Obama administration and that is why suddenly we've seen so many parents, so many states, so many school districts reject it so harshly," Abbott said.

And then there was the you "can't change the nature of math" argument made by Bennett.

Which prompted Abbott to direct viewers to this video of teacher explaining how 9+6 is taught in common core schools:

Why does this matter for 2016? Because Jeb Bush, the nominal GOP frontrunner, has been a strong Common Core supporter while Florida Sen. Marco Rubio, Louisiana Gov. Bobby Jindal and Kentucky Sen. Rand Paul have been skeptical of the nationalized standards.  Expect to see a repeat of the Bennett-Abbott argument on a 2016 debate stage soon enough.