Trump, who has campaigned frequently in the state, received 40 percent in the poll, giving him a 2-to-1 advantage over the rest of the field. In the race for second place were Governor John Kasich of Ohio and Senator Marco Rubio of Florida, tied with 19 percent each. In fourth place was Senator Ted Cruz of Texas, at 10 percent, followed by retired doctor Ben Carson with 5 percent, according to the survey.

The WBUR survey, conducted by The MassINC Polling Group, showed former secretary of state Hillary Clinton edging out Senator Bernie Sanders, 49 percent to 45 percent — a lead just within the poll's margin of error of 4.9 percentage points.

A new poll shows a competitive race for Tuesday's Democratic presidential primary in Massachusetts, while New York businessman Donald Trump towers over his opponents in the GOP race.


The Massachusetts race could be critical to Sanders. He will likely lose Saturday's primary in South Carolina, and his aides have said he can only feasibly win a few of the 11 states with Democratic primary contests on Super Tuesday. Sanders leads in polls of his home state of Vermont and remains competitive with Clinton in Colorado, Minnesota, Oklahoma, and Massachusetts.

"Massachusetts is really a must-win for Senator Sanders," said Tufts University political science professor Jeffrey Berry. "If he loses liberal Massachusetts, the question will then arise, 'Where can he win?' I think that goes a long way in explaining why he's spending time and resources here."

Sanders campaigned Monday in the state, stopping in Boston for a press conference and at the University of Massachusetts Amherst for a rally.

The poll also showed Massachusetts Democrats had strong feelings about their chosen candidate. Clinton led Sanders, 70 percent to 22 percent, on the question of who can best handle foreign policy. But Democrats trusted Sanders over Clinton to address income inequality, 61 percent to 30 percent.


According to the poll, part of Trump's appeal is his position on the economy. Three out of five Republicans surveyed said Trump would do the best on jobs compared to everyone else in the GOP field.

The poll also asked whether President Obama should nominate someone to fill the current vacancy on the Supreme Court or whether that should be the job of the next president.

By an overwhelming number, 83 percent to 13 percent, Democrats said Obama should nominate someone. The results for Republicans was mixed: 41 percent said Obama should do it, while 55 percent said this duty should be left to the next president.

The poll was conducted Sunday through Tuesday. The Democratic poll surveyed 419 likely Democratic voters, while the Republican sample included 386 likely GOP voters.

James Pindell can be reached at james.pindell@globe.com. Follow him on Twitter @jamespindell or subscribe to his daily e-mail update on the 2016 campaign at www.bostonglobe.com/groundgame