Presidential candidate Jill Stein fired back at Bay State U.S. Sen. Elizabeth Warren for claiming that a vote for the Green Party nominee could only help Donald Trump.

Stein, a Lexington physician lagging far behind in the polls — pulling only single digits — said votes still need to be “earned.”

“Politicians are not ‘entitled’ to our votes simply because they represent the establishment political parties,” she said in an email to the Herald.

“With a majority of Americans rejecting (Hillary) Clinton and Trump with record high levels of dislike and distrust, neither of them has earned our votes. I say: Don’t waste your vote on politics as usual that’s throwing us under the bus. Invest your vote in a movement for real change,” Stein said in a statement.

After a speech Thursday at Roxbury Community College, Warren said a vote for Stein — instead of Democratic presidential nominee Clinton — effectively would be one for Trump, whom she called a “racist bully.”

“Anything you do that helps Donald Trump get one inch closer to the White House is a danger to all of us,” Warren said, adding that a vote for Stein “moves Donald Trump closer to the White House.”

By yesterday afternoon, Stein, who also was the Green Party nominee in 2012, shot back on Twitter, saying: “Sad to see @elizabethforma attacking real progressives on behalf of a Wall Street-financed campaign. #WalkTheWalk”

That prompted one woman to tweet: “Hey @elizabethforma recall what it means to be an actual progressive with integrity? #WalkTheWalk #JillNotHill”

Nationally, Stein is polling at 3.4 percent, trailing Clinton’s 42 percent, Trump’s 37 percent and Libertarian Gary Johnson’s 9 percent, according to a Real Clear Politics average of polls.

Earlier this month, the Commission on Presidential Debates announced that only candidates receiving 15 percent support nationwide according to five polls that will be averaged together will qualify for the presidential debates, which will begin in late September.

But that doesn’t necessarily mean that neither Stein nor Johnson could receive enough votes to sway the results of the election.

In 2000, for example, Green Party nominee Ralph Nader won more than 97,000 votes in the swing state of Florida, costing Democrat Al Gore the state and, ultimately, the presidency.

In an interview Tuesday, however, Stein dismissed the idea that she could turn out to be a spoiler.

“We’re in a very different moment now historically than we were in 2000 because the majority of American voters have rejected both Hillary Clinton and Donald Trump,” she told PBS NewsHour’s Judy Woodruff. “They’re the most disliked and untrusted candidates for president in our history.”