U.S. Sen. Bernie Sanders, I-Vt., celebrates his victory on Tuesday, Nov. 6, 2012 in Burlington, Vt. (AP Photo/Toby Talbot)

Sen. Bernie Sanders (I-Vt.) is still considering running for president in 2016, but he's not sure under which banner.

In an interview with Tavis Smiley, Sanders said he's not sure whether he would run as an independent/third-party candidate or in the Democratic primary. (Sanders caucuses with Democrats.)

If he did run outside the Democratic Party, Sanders also said he won't be a "spoiler" -- i.e. a third-party candidate who runs and takes enough of the vote from the Democratic nominee to allow the Republican to win.

"I will not be a spoiler; that I will not allow myself to be," Sanders said. "I am not going to be put into a position where we allow some right-wing Republican to become president because of something that I might do."

Sanders added: "There are ways to deal with that, which I don't -- we're thinking about right now, and I don't want to get into at great length right now. But there are ways to make sure that, in fact, one doesn't become a spoiler."

Sanders has said he might run if the field of candidates doesn't include a strong liberal voice.