A Louisiana judge ruled against Gov. Bobby Jindal’s fight to delay Common Core implementation, clearing the way for state schools to move forward with the controversial standards this fall.

The judge on Tuesday issued a preliminary injunction against Jindal’s action, saying that the governor’s attempt to unilaterally repeal the educational standards would cause “irreparable harm” to the state’s students and teachers. Jindal is challenging his decision.

The governor’s chief of staff, Kyle Plotkin, said “We think this judge is wrong on the facts and the law. Hopefully, he will reconsider this preliminary ruling at the full trial. In the meantime, we will seek a stay of this ruling and an expedited writ to appeal to the First Circuit.”

Jindal (R) had previously said the lawsuit – which was organized by education advocacy groups – had “no merit.” A week later, many of his own appointees at the Louisiana Board of Elementary and Secondary Education voted to join the lawsuit.

The ruling is a major blow to the potential 2016 presidential contender. Jindal’s staunch opposition of Common Core has also puts him at odds with one of the biggest names within his own party, Republican Sen. David Vitter – who is also likely Jindal’s successor as governor.

Vitter emerged this week as a surprisingly strong supporter of Common Core. Blasting Jindal’s approach to the standards as “very disruptive” to Louisiana schools, Vitter pledged to help school boards implement Common Core.

The Tea Party of Louisiana expressed “shock and outrage” at Vitter’s position.

“Sadly, Senator Vitter’s remarks sound more like the rhetoric we’d expect from a D.C. elitist who doesn’t believe that we average citizens are capable of making our own decisions, running our own lives, and raising our own children,” spokesman Bob Reid wrote in a statement to the Times-Picayune.

Jindal and Vitter – two of Louisiana’s best known politicos – are also longstanding rivals.

When Jindal tried to build a $1.2 billion teaching hospital for New Orleans in 2010, Vitter wrote a letter to the U.S. Housing and Urban Development secretary to warn against the project. In return, Jindal refused to back the senator’s reelection campaign in 2010. Vitter has also repeatedly accused Jindal of mismanaging the state budget.

Common Core is one of the most divisive issues in Louisiana politics – and the subject of three lawsuits in the state. More than a dozen Republican lawmakers filed a lawsuit against the state’s education board in July, their latest attempt to dilute the standards. A bill to repeal Common Core had already failed in the legislature.

Indiana became the first state to ditch the national standards in March, with lawmakers in Oklahoma and South Carolina following suit. Missouri Gov. Jay Nixon (D) also signed a bill to replace Common Core this summer.