Sen. Bernie Sanders, an Independent from Vermont, who made college-debt a centerpiece of his ultimately unsuccessful 2016 campaign for the Democratic presidential nomination, announced Tuesday that he’s running for president, again.

The American Federation of Teachers and the National Education Association endorsed Sanders’ opponent for the Democratic nod in 2016, Hillary Clinton, to the chagrin of many of their members. Sanders addressed AFT’s convention last year and gave the teachers a pat on the back for hitting the picket lines to push for higher wages and more money for education.

“As part of this political revolution, teachers are standing up and leading the fight for education reform,” he said. “Who would have thought that in West Virginia or Kentucky, in Oklahoma, teachers are demanding decent education for our kids and are taking on right-wing political establishments? Thank you, teachers.”

As a presidential candidate in 2016, Sanders wanted to make public college free for everyone, and pay for it by taxing Wall Street. (He’s reupped that vision. And he made one bold proposal on K-12: moving away from property taxes to a more equal system of funding education.)

He’s also recently sponsored bills on dual enrollment, community schools, and is the author of the DIPLOMA Act, which would offer grants to states to improve outcomes for disadvantaged children.

Back in 2001, as a member of the House of Representatives, Sanders voted against the No Child Left Behind Act because of its emphasis on standardized testing. And in 2012, Sanders was slated to meet with “Occupy the DOE” protestors about the opt-out movement. (That means he was opt-out long before opt-out was cool.)

But in 2016, as a presidential candidate, Sanders took a slightly different tack when it came to testing and accountability. Along with just about every other Democrat in the Senate, he supported an amendment by Sen. Chris Murphy, D-Conn., that would have beefed-up accountability in the Senate version of what became the Every Student Succeeds Act. And he got some blowback for that position from teachers across the country who support him.

Sanders wasn’t a fan of President Barack Obama’s education redesign agenda. He argued that big competitions like Race to the Top shortchanged rural states like Vermont. And back in 2011, when Congress was working on an (ultimately unsuccessful), renewal of NCLB, he introduced an amendment that would make it tougher for alternative-route teachers to be considered “highly qualified.”

Photo: Patrick Semansky for the Associated Press