Jan. 18, 2010 -- It's the last place Democrats would expect to see as a battleground state. But the fight for the Massachusetts Senate seat occupied by the late Sen. Ted Kennedy for 46 years is heating up, and President Obama is in the middle of it all.
The names on the ballot are Democrat Martha Coakley, 56, and Republican Scott Brown, 50. But the stakes are high not just for the candidates, but also for the president and Democrats around the country.
If the special election to be held Tuesday goes to Brown, Senate Democrats will lose the 60-seat majority they currently enjoy and that they need to pass a health care bill and other Democratic items.
Coakley today unveiled a new TV ad featuring Obama stumping for her on Sunday in Boston.
"Every vote matters, every voice matters. We need you on Tuesday," Obama is shown saying at the rally Sunday, where, in a scramble to save Kennedy's seat, he made a last-minute stump speech for Coakley and attempted to rile up the Democratic base that dominates the state.
"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.
"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."
While the president tried to rally the crowd, he attempted to distance himself from the election, even though he seemingly was well informed about it. Obama also acknowledged voter anger and frustration, which Brown has tapped into in his campaign.
But Obama steered clear of the topic of health care overhaul, which has become the focal point of this high-profile race.
Brown, a lawyer and former model, has vowed to vote against health care overhaul if he is elected.
"As the 41st senator I can at least allow them to, you know, maybe look at things a little differently," Brown told ABC News in an interview.
If Massachusetts Attorney General Coakley loses, as polls indicate she might, Democrats want to be in a position to pass a bill through the Senate before Brown is sworn in, which wouldn't leave Democrats much time to hash out a compromise between the House and Senate bills.
Sources say that in case of a Democratic loss, the White House would want the House to vote directly on the bill Senate passed on Christmas Eve. House Speaker Nancy Pelosi, D-Calif., has told White House officials they don't have enough votes to pass that legislation, but administration officials argue that if it's not the Senate bill, there may not be any health care overhaul.
Another idea House Democrats are discussing assuming Brown wins is having Senate Democrats force the bill through by bypassing normal Senate rules and passing the legislation through reconciliation, which requires only 50 votes. That would allow some moderates to peel away.
"There's no question that the president's domestic agenda hangs in the balance," said Democratic commentator Donna Brazile.
Massachusetts Senate Race Heats Up
That's the reason the president on Sunday 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."
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?" he asked.
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.
"And it's clear now that the outcome of these and other fights will probably rest on one vote in the United States Senate," he said.
National Democrats are shocked that the race seems this close, given that Democrats outnumber Republicans in Massachusetts 3-1. Some say it is less about the president and more about a weak candidate.
But some Republicans say the mere closeness of the race spells troubles for Democrats.
"Whether Coakley wins or loses, the message is the same, health care. This health care package is death for candidates," said conservative commentator Tucker Carlson.
As Massachusetts voters head to the polls Tuesday, both candidates are stepping up their campaigns.
Coakley today invoked the memory of civil rights leader Martin Luther King Jr., to make her pitch.
"If Dr. King were here today, he'd be standing with us," she said. "And I know that he would be standing with us on the front line for health care, not as a privilege, but as a right."
ABC News' Jake Tapper, Jonathan Karl and Kristina Wong contributed to this report.