Boston (AP) - In a contest with major national implications, Massachusetts voters chose a successor to the late Sen. Edward M. Kennedy on Tuesday in a down-to-the-wire election that became a referendum on President Barack Obama's sweeping health care overhaul and his first year in office.
A loss - or even a narrow victory - by once-favored Democrat Martha Coakley to insurgent Republican Scott Brown in this Democratic stronghold could signal big political problems for the president's party this fall when House, Senate and gubernatorial candidates are on the ballot nationwide.
More immediately at stake was a critical 60th vote for Democrats to save their health care legislation and the rest of Obama's agenda. A 41st Republican in the 100-member Senate could allow the GOP to block the president's priorities with filibusters.
The election transformed reliably Democratic Massachusetts into a battleground state. One day shy of the first anniversary of Obama's swearing-in, it played out amid a backdrop of animosity and resentment from voters over persistently high unemployment, industry bailouts, exploding federal budget deficits and partisan wrangling over health care.
Days before the vote, White House advisers and other Democrats in Washington began making excuses for they called a poorly run campaign on Coakley's part. Obama flew to Boston for last-minute personal campaigning on Sunday.
Wall Street watched closely. The Dow Jones industrial average rose 116 points, and analysts attributed the increase to hopes the election would make it harder for Obama to make his changes to health care. That eased investor concerns that profits at companies such as insurers and drug makers would suffer.
Across Massachusetts, voters who had been bombarded with phone calls and dizzied with nonstop campaign commercials for Coakley and Brown gave a fitting turnout despite intermittent snow and rain statewide.
Boston reported twice the primary turnout among early voters, while in western Massachusetts, one in five registered voters in Longmeadow had shown up by 11 a.m.
Secretary of State William Galvin predicted turnout ranging from 1.6 million to 2.2 million, 40 percent to 55 percent of registered voters. The Dec. 8 primary had a scant turnout of about 20 percent.
As polls opened, Brown drove up to his polling place in Wrentham in the green pickup truck that came to symbolize his upstart, workmanlike campaign that in the past week pulled him into a surprise dead heat in polls.
"It would make everybody the 41st senator, and it would bring fairness and discussion back to the equation," the state senator said of a potential victory. He spent the rest of the day out of public view, crafting evening rally remarks that had the potential to be an early State of the Union speech for the national Republican Party.
Coakley, stunned to see a double-digit lead evaporate in recent weeks, counted on labor unions and reawakened Democrats to turn out on her behalf and preserve a seat Kennedy and his brother, President John F. Kennedy, held for over 50 years. The senator died in August of brain cancer.
"We're paying attention to the ground game," Coakley, the state's attorney general, said casting her vote in suburban Medford. "Every game has its own dynamics."
Liz Sidoti reported from Washington. Associated Press writers Beth Fouhy, Steve LeBlanc, Karen Testa, Kevin Vineys, Stephanie Reitz and Matthew Daly also contributed to this report.
In a contest with major national implications, Massachusetts voters chose a successor to the late Sen. Edward M. Kennedy on Tuesday in a down-to-the-wire election that became a referendum on President Barack Obama's sweeping health care overhaul and his f