Vermont Sen. Bernie Sanders Bernie SandersNYT editorial board remembers Ginsburg: She 'will forever have two legacies' Two GOP governors urge Republicans to hold off on Supreme Court nominee Sanders knocks McConnell: He's going against Ginsburg's 'dying wishes' MORE (I) says he will decide by March whether to run for president in 2016.

"I don't want to do it unless I can do it well," the independent senator told the Associated Press in an interview published Friday. "I don't want to do it unless we can win this thing."

ADVERTISEMENT

Sanders said it would be a "gut decision," and that he is still unsure if he would run as an independent or a Democrat, setting off a potential primary challenge from the left to likely frontrunner Hillary Clinton.

Sanders would be 75 years old next year, but said that his "health is good."

Sanders's comments are only the latest sign that the Vermont senator is serious about a 2016 run.

While polls show that former Secretary of State Clinton is the clear frontrunner for the Democratic nomination, a number of progressive groups have pushed for a liberal challenger. MoveOn.org is seeking to draft Sen. Elizabeth Warren (D-Mass.), but she has denied plans to run.

Earlier this month Sanders traveled to early-voting Iowa to deliver a speech to a progressive group.

Last month, a veteran Democratic strategist, Tad Devine, signed on to help his possible campaign. Devine was a top adviser to Al Gore in 2000 and to John Kerry in 2004.

In the interview, Sanders cited growing income inequality as motivating his possible bid, arguing that the middle class is "collapsing."

"You have one family, the Walton family of Walmart, owning more wealth than the bottom 40 percent of the American people," he told the AP.

"We have 95 percent of all new income going to the top 1 percent. You have millions of families unable to afford to send their kids to college," he continued. "People are desperately worried about whether or not they are going to retire with dignity."