On Sunday in Boston to promote Coakley's candidacy, Obama tied Brown's agenda to "Washington Republicans" who are against financial reform, clean energy and health care reform.
"When the chips are down, when the tough votes come, on all the fights that matter to middle class folks of the Commonwealth, who is going to be on your side?" the president asked the crowd at Northeastern University in Boston.
Meanwhile, Brown disregarded the president's rhetoric yet seized on that same message of change that Obama successfully ran on in his own presidential campaign.
"They are tired of business as usual," Brown said. "They want someone who isn't part of the machine or an insider."
Joseph L. Kennedy, a Libertarian who is running as an independent, is also on the ballot but he hasn't been in the forefront. He has no relation to the Kennedy family.
While the president tried to rally the crowd on Sunday, he also attempted to distance himself from the election. Obama also acknowledged voter anger and frustration, which Brown has tapped into in his campaign.
"Where we don't want to go is backwards towards the same policies that got us into this mess in the first place. We have had one year to make up for eight. It hasn't been quick, it hasn't been easy, but we're beginning to deliver on the change you voted for," the president said. "A lot of these measures are going to rest on one vote in the U.S. Senate."
Obama steered clear of the topic of health care overhaul, which has become the focal point of this high-profile race.
The president instead took a swipe at Brown's description of himself as someone who drives a truck.
"I'd think long and hard about getting in that truck with Martha's opponent," the president said. "It might not take you where you want to go."
"If you were fired up in the last election, I need you more fired up in this election! I need you, I need you!" Obama told the crowd, estimated to be around 1,100.
Coakley today addressed the issue of economy that Brown has made the defining feature of his populist campaign.
"I wish there were easy answers to the tough problems we have," she said at a breakfast today commemorating Martin Luther King Jr. "Do not forget that they are problems that were not created by, but inherited by, our president, Barack Obama."
Candidates on both sides of the tight race have seen money and resources pouring in for their campaigns. Brown raised more than a million dollars online every day last week, according to a Republican source familiar with his fundraising. Bush administration official Karl Rove told his twitter followers to phone bank. Sen. John McCain called on to his supporters to back Brown.
On the other side, Democratic groups placed more than 500,000 calls on Saturday. Former president Bill Clinton appeared with Coakley at two campaign events, and Kennedy's widow, Vicki, appeared in a television ad to support the attorney general. Last week, Obama taped a robo-call in support of Coakley.
"In Washington, I'm fighting to curb the abuses of a health insurance industry that routinely denies care. I'm fighting for financial reforms to stop Wall Street from playing havoc with our economy. I'm fighting to create a new clean energy economy," the president said in the call.