They’re battling for second place behind former Vice President Joe Biden in the Democrats' race for the presidential nomination, but Sens. Bernie Sanders of Vermont and Elizabeth Warren of Massachusetts – at least publicly – aren’t taking aim at each other.

That’s been the case since the two quietly met last December – before they launched their White House bids – and agreed not to take jabs at each other on the campaign trail.

It remained the case on Monday, as both of the progressive and populist standard bearers in the party refrained from criticizing each other while they both campaigned in neighboring New Hampshire, the state holding the first primary in the presidential race.

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“Bernie and I have been friends for many, many years, long before I ever got into politics, and I don’t see any reason that that should change,” Warren told reporters after being asked if she was going to end the non-aggression pact with Sanders.

And, Warren repeated another line she often has used, saying that rather than jabbing at Sanders, she would continue to “get out every day and try to meet as many voters as I can and talk about why I’m in this race, to talk about what’s broken, to talk about my plans to fix it and to talk about how I’m building a grassroots movement to get it done. I think that’s what voters want to hear - what’s your positive message.”

Warren’s campaign said it drew roughly 800 people to an outdoor house party during a rainy afternoon in New Hampshire’s Seacoast region.

About 90 minutes west of Hampton Falls, Sanders was holding a town hall in Peterborough. His campaign highlighted that more than 800 were in attendance, according to the fire marshal.

Earlier, Sanders marched in the Milford Labor Day Parade, the largest annual Labor Day parade in New Hampshire. He was the only candidate marching in this year's parade.

Asked by Fox News if he was disappointed that none of his rivals joined him, Sanders passed on the opportunity to take aim at any of his opponents. Instead, he said, “ask them.”

Sanders - who crushed eventual nominee Hillary Clinton in the 2016 New Hampshire presidential primary in what was basically a two-candidate race - then touted that “we’re going to spend a lot of time in New Hampshire. We did well in New Hampshire last time, but we’re not taking anything for granted.”

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Sanders – as he has throughout his second White House bid – refrained from calling New Hampshire a “must win” state.

“This is obviously a very important state, as is Iowa, South Carolina. We’re working hard. We’re going to do many, many rallies around the state, and I’m feeling pretty good,” he explained.

But, a veteran Granite State-based political scientist said the first primary state’s crucial to both candidates and predicted the gloves may soon come off.

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“New Hampshire is a must-win-or-place state for Senators Sanders and Warren,” said Wayne Lesperance, the vice president of academic affairs and a political science professor at New England College. “For both candidates, there is no better home-field advantage in the early states than the Granite State.”

Pointing to the upcoming third round of presidential primary debates, he explained, “With the end of summer, I expect we will see the end of collegiality between the two leading progressive candidates. The September debate should feature fireworks as both begin to look ahead to fall and winter in New Hampshire.”