UPDATED

Add one more unabashed Common Core State Standards foe to the list of Republican presidential candidates: Sen. Rand Paul, R-Ky.

Paul, who officially entered the presidential race Tuesday, has relentlessly tweaked former Florida Gov. Jeb Bush for his support of the standards, saying last fall that any “hypothetical” GOP presidential hopeful who likes the common core “doesn’t have much chance of winning in a Republican primary.”

And earlier this year, Paul’s camp put out a memo that slammed his GOP rivals for their championship of the standards. (There were a lot of inaccuracies about the common core in that memo. Plus, some of the folks on the list, like Gov. Scott Walker of Wisconsin, aren’t as closely associated with support of the standards as say, Bush.)

In the Senate, Paul is a member of the education committee. So far this year, he’s co-sponsored legislation by Sen. Pat Roberts of Kansas that would bar the feds from getting involved in standards. He’s also lent his support to a bill by Sen. Mike Crapo, R-Idaho, that would prohibit the feds from interfering with local decision-making on standards, curriculum, and assessments.

In fact, the Crapo bill would prohibit the federal government from mandating testing at all. That flies in the face of both the current version of the No Child Left Behind Act (which calls for testing in grades 3 through 8 and once in high school) and the in-the-works compromise legislation to rewrite NCLB being worked out between the two top lawmakers on the education committee, Sen. Alexander, R-Tenn., the chairman, and Patty Murray, D-Wash., the ranking member, which would keep the testing schedule intact.

And, for those keeping score, Sen. Ted Cruz, R-Texas, who seems to be vying with Paul to be the number one tea-party superhero in the Republican field, is also a co-sponsor of Crapo’s bill.

But Alexander and Paul have been school choice buddies in recent years, a partnership which has a clear political upside for both lawmakers. Back in March of 2013, they teamed up on a budget amendment that would have allowed Title I dollars for disadvantaged kids to follow students to any school of their choice, even a private school.

In fact, Paul mentioned school choice in his official presidential announcement, “We need to stop limiting kids in poor neighborhoods to failing public schools and offer them school choice,” he said.

Paul is also not afraid to use Senate rules and procedures to block education legislation he doesn’t like. Back in 2011, he initially introduced more than 70 amendments during committee consideration of a bipartisan bill to rewrite the NCLB law—and put up procedural roadblocks aimed at slowing down the bill.

Paul’s entrance into the GOP race is sure to energize home schoolers and the anti-common-core crowd. A bigger and maybe more immediate question through: What does it mean for Senate consideration of the NCLB rewrite bill?

If the compromise isn’t conservative enough for Paul, he may decide to gum up the procedural works again—or lead the charge against the bill in committee and then on the Senate floor.

It’s an issue to keep your eye on as the GOP presidential primary and the NCLB rewrite start to converge.

Paul has added a section on education to his campaign website. (He might want to see about bringing a spelling bee champ or two onto his staff. Highlight added.)

Sen. Rand Paul, walks from the stage after speaking during the Conservative Political Action Conference (CPAC) in National Harbor, Md., last February.--Carolyn Kaster/AP