Fallon characterized the endorsement as an issue of character, rather than partisan politics, and called it an "easy" choice.

"We know where your heart is and we know that your heart is with the people of Massachusetts," he said.

That makes 18 current or former Democratic Massachusetts politicians who are backing Brown, and the Democrats for Brown coalition includes 500 grassroots supporters as well. It's chaired by some of Brown's most prominent Democratic backers — former Boston Mayor Ray Flynn, former Springfield Mayor Charles Ryan and former Worcester Mayor Konstantina Lukes.

Most of the politicians in the coalition, however, are no longer in office, which reduces the possible political backlash of snubbing the Democratic nominee.

However, Brown hopes it will help him win over independents in Massachusetts, which make up more than 50 percent of the electorate. Though the state has historically backed Democrats, and is overwhelmingly supporting President Obama, the Senate race remains close, largely due to how well-liked Brown is in the state.

He's been focusing on building up support based on that likeability, rather than attacks on his opponent, Elizabeth WarrenElizabeth Ann WarrenDems demand end to waivers used to pay people with disabilities below minimum wage A new progressive standard on campaign cash: It can't come from corporations Kamala Harris will no longer accept corporate PAC money MORE, with ads featuring him talking to average Massachusetts citizens or touting his own achievements in Congress.

The most recent slate of ads has featured Brown sitting behind the wheel in his pick-up truck, which he frequently mentions during campaign appearances — a way to connect with blue-collar voters.

The newest in this series of "Scott Brown from the Road" ads, launched on Friday, features Brown talking about the success of the Stop Trading on Congressional Knowledge Act, which made insider trading illegal. Brown was one of the most prominent supporters of the bill, and the ad features footage of him shaking President Obama's hand after he signed the bill into law.

"For me, it's pretty simple. The politicians? They should live by the same laws as everyone else," Brown says at the end of the ad.

It's another brick in the narrative Brown's building of an incumbent Senator fighting for the little guy. His campaign hopes that just that narrative, and the Democratic support Brown's touting with his new coalition, could help push him over the edge with voters skeptical of his party affiliation.

Watch the ad: