US Sen. Elizabeth Warren said she plans to serve out her six-year term if she's re-elected this year.

"It's certainly my plan," Warren, D-Cambridge, told the Dorchester Reporter's news editor Jennifer Smith during a town hall at the Boston Teachers Union building.

Warren, first elected in 2012, is frequently mentioned in national media outlets as a possible 2020 presidential contender.

Speaking with other reporters after the event, Warren offered the same answer on serving out her term if re-elected: "Yes, that's my plan."

The GOP candidates jockeying to take her on in November 2018 frequently point to her national profile as an indication she is interested in the White House. The candidates are state Rep. Geoff Diehl, former Mitt Romney aide Beth Lindstrom and businessman John Kingston.

Asked again if she's committing to a six-year term if re-elected, Warren said, "I'm running for the United States Senate in 2018. I am not running for president of the United States. That's my plan."

Warren covered a range of issues during the town hall, putting a dollar figure on a proposal to spend $100 billion over ten years to curb the opioid epidemic across the country.

Warren is scheduled on Friday to visit the Boston Healthcare for the Homeless Program and introduce the opioid crisis legislation with US Rep. Elijah Cummings, D-Maryland.

Warren also took audience questions from the friendly crowd. One person asked about impeaching President Donald Trump, who has frequently clashed with Warren.

"I want to be sober about this because this is serious business," Warren said. "Right now, I believe it is absolutely critical that the special counsel, [Robert] Mueller, be allowed to complete his investigation in full with no interference from anyone," Democrat or Republican.

Asked about the state of the MBTA, which sometimes struggles to provide reliable service, Warren said, "You get what you pay for."

The public transit system has seen under-investment for 30 years, and while she says she helped get federal funds for a Green Line extension project, it's "not nearly enough."

Asked after the town hall forum whether that means she supports a millionaires income tax proposal headed for the 2018 ballot in Massachusetts, Warren said," Yes." Advocates of the proposal say it would funnel more money to education and transportation funding accounts.

During the lightning round of questions, Smith, a coffee connoisseur, asked Warren which brand she prefers. "Is it really Dunkin'?" Smith asked, referring to the brand based in Canton, Mass.

"Uh," Warren said.

When Smith pressed her, Warren said, "I'm going to have to come clean on this. I don't drink coffee."