The race for the congressional seat in Massachusetts' 6th District on the north shore of Boston is hot enough to boil over. Since Seth Moulton’s upset win in the Democratic Primary over 9-term incumbent John Tierney, three candidates are jostling for endorsements, media coverage, and the support of voters in the district. The race is sure to be close.

All three candidates have positioned themselves as Washington outsiders, blurring the distinction for voters in the general election.

Richard Tisei, the Republican challenger, lost to John Tierney by less than 5,000 votes when the seat was last contested in 2012.

It is unclear how much of the support for Tisei at that time was a backlash against Tierney or a sign that the district was shifting to the right. Tierney was then battling accusations that he was complicit in his wife's financial wrongdoings, resulting in her conviction on federal charges.

campaign as a fresh choice for the House seat. He served in the Massachusetts Legislature from 1985-2011. But he is not your typical Republican.

Openly gay, Tisei married his longtime partner, Bernie Starr, in 2013. Socially moderate, he has been vocal in his opposition to the Republican platform on same-sex marriage and abortion. Fiscally, he favors reigning in spending to balance the budget.

"I can be a real change agent in Washington," said Tisei at a recent campaign event. "I will be able to hit the ground running on day one and I think I'll be able to do more for the state."

Seth Moulton, the Democratic nominee, is a 35-year-old ex-marine and Iraq war veteran. In his campaign against incumbent Tierney, he firmly positioned himself as a Washington outsider and won by a comfortable margin.

Moulton’s campaign labels him as a progressive Democrat -- part of a new generation of leaders who can fix Washington. He believes strongly in service. In the words of his mentor, the late Rev. Peter Gomes, "Believing in the right thing is not good enough... you ought to go do it."

"I am working hard to earn the support of the former supporters of Congressman Tierney,” Moulton recently told WGBH news.

He just picked up a key endorsement from Senator Elizabeth Warren, who supported Tierney in the primary.  On Tisei, Moulton says, “no matter how moderate he is, he’s still going to support the national Republican agenda in Washington.”

Independent candidate Chris Stockwell is also vying for the seat. Stockwell, a local business and community leader, offers his own new perspective to the district, claiming that the election is a referendum on the broken political system.

Richard Tisei calls himself “a problem solver who works across party lines to get things done.”

Seth Moulton has been described as being “dedicated to reaching across the aisle and making true progress.“

The common theme is plain to see: 3 candidates; 3 Washington outsiders; 3 fresh choices, each offering an alternative to the status quo.

Any of these candidates could effectively use this approach versus a long-time incumbent. However, with John Tierney’s absence on the ballot, their respective messages no longer have a clear target. It is difficult to discern the uniqueness of their positions.

Chris Stockwell may offer the best response to this conundrum: he is running, he claims, not against either of the other candidates, but against the parties they represent. At a recent campaign event in Lynn, Massachusetts, Stockwell stated:

“I want the message sent loud and clear throughout the nation that the parties are not accomplishing the business of the people effectively so we don’t need to elect them again.”

Shifting the balance of power in Washington, Stockwell said, can only happen by electing unaffiliated independents, rather than parties that have gone off the reservation.

A recent article in the Boston Globe about the race makes no mention of Stockwell, focusing solely on Tisei and Moulton, who the paper says “are now on a collision course.”

Granted, the major party candidates have a clear advantage in fundraising and spending potential to reach voters. With limited time left in the campaign, Stockwell responds:

“People are smart; they are looking for a new approach. They can line you up against someone else and make a decision pretty quickly.”

Which of these outsiders will voters in the district send to Congress on November 4? It will be interesting to see if the victor will be able to make good on his promise to promote change in Washington.