Sen. Lamar Alexander, who was the president of the University of Tennessee and was education secretary during the George H. W. Bush administration, slammed the National Labor Relations Board's ruling Tuesday that teachers assistants are eligible to unionize.

The Tennessee Republican and chairman of the Health, Education, Labor and Pensions Committee warned that the ruling "was a shameless ploy to increase union membership rather than a genuine attempt to help students."

The ruling, released Tuesday, said that "student assistants who have a common-law employment relationship with their university are statutory employees under the act." The decision came in a case involving efforts by the United Auto Workers to unionize teachers assistants at Columbia University.

The labor board is the federal government's main labor law enforcement agency. It currently has a four-member board, three of whom are Democrats. Tuesday's ruling was 3-1, with the board's lone Republican dissenting.

Republicans have long accused the labor board under President Obama of repeatedly bending the rules to aid unions. Alexander said Tuesday's ruling proved the point.

"Today, the NLRB has again changed its policy to benefit unions by allowing 'student assistants' at private colleges to unionize — completely confusing the entire reason students enroll in the first place; if I'm earning a BS or an MBA from Union University in Jackson or an advanced engineering degree from Vanderbilt, my primary purpose and benefit during my time there is to gain the skills I need to launch myself into the career and the future I want — not to garner wages as an employee of the university," Alexander said.

The senator said the ruling was more likely to harm the assistants rather than help them.

"The result may well be colleges ending undergraduate student assistant programs so that 18-year-old freshmen aren't dealing with union reps rather than focusing on their degree. It will create confusion for hundreds of colleges and universities," he said. Alexander has previously sponsored legislation to rein in the labor board.

Unions have praised the ruling. "Our union and hard-working graduate employees at some of our nation's premier universities have never wavered in our pursuit of workers' rights for tens of thousands of workers abandoned by the Bush-era Brown University decision in 2004," said Julie Kushner, director of UAW Region 9A.