The Republican presidential candidates were deep in the South Thursday night — Texas, to be exact — battling in the last debate before the Super Tuesday primaries. But it may be a state in the North that helps determine the ceiling for front-runner Donald Trump's campaign. 

Massachusetts votes March 1, also known as Super Tuesday due to the amount of states that hold their primaries. And while Democrats will of course be watching their own party's tight race between front-runner Hillary Clinton and Vermont Sen. Bernie Sanders, they will also be keeping their eyes on the Republican race. Massachusetts is one of the only largely liberal states up for grabs on Super Tuesday, so it will be an early barometer for how Donald Trump, if nominated, might fare in a general election.

"It’d be like the canary in the coal mine," Democratic strategist Doug Rubin told Politico. "If Trump is able to convince a lot of moderate-to-conservative independents to vote in the primary and he does really well here, that would be a warning sign for Democrats going forward."

Trump promised as much in the debate Thursday during a response to a question about his support from Hispanic voters. In a bit of a redirect, the candidate discussed how he was helping to build a new, broader coalition of Republican voters. 

"I’m going to be getting — bringing a lot of people in who are Democrats, who are independents, and you’re seeing that with the polls, because if you look at anywhere, look at any of the elections, every single election, it has been record-setting," said Trump. "New people are coming into the Republican Party. We are building a new Republican Party; a lot of new people are coming in."

Donald Trump Republican Presidential candidate Donald Trump speaks to the media Thursday after the Republican National Committee Presidential Primary Debate in Houston. The upcoming primary in Massachusetts could be a test of Trump's general election viability. Photo: Joe Raedle/Getty Images

Meanwhile, Trump's Republican rivals criticized the front-runner for not being a true conservative. 

A poll of likely voters by Boston NPR affiliate WBUR concluded that Trump currently holds a comfortable lead in Massachusetts with 40 points. Florida Sen. Marco Rubio and Ohio Gov. John Kasich are tied for a distant second with 19 points. Texas Sen. Ted Cruz and Dr. Ben Carson rounded out the field with 10 points and 5 points, respectively. 

The Democratic and Republican Massachusetts primaries will be held March 1. More than a dozen states and hundreds of delegates will be in play on Super Tuesday.