U.S. Sen. Scott Brown and his remaining Democratic challengers have already raised more than $8 million combined for an election a year away, signaling what will likely be a costly, hard-fought Senate race, political observers said.

U.S. Sen. Scott Brown and his remaining Democratic challengers have already raised more than $8 million combined for an election a year away, signaling what will likely be a costly, hard-fought Senate race, political observers said.


“I would expect it to be one of the highest-spending races in the country,” said Marty Linsky, a longtime lecturer at Harvard University’s Kennedy School of Government.


Brown, a Republican from Wrentham, had $10.5 million in his campaign war chest as of Sept. 30, hauling in about $4.8 million of that total since January, according to campaign finance records.


Until Democrat Elizabeth Warren, a Cambridge resident, entered the race this fall, Brown’s next closest rival in fundraising was City Year Alan Khazei, who had raised $1.3 million by September’s end.


Following Khazei was Newton Mayor Setti Warren, who dropped out of the race at the end of September having raised a total of $226,668, but with $136,084 in debt.


Elizabeth Warren’s arrival changed the landscape as she managed to pull in $3.15 million in a single quarter. While four other Democrats are still vying for the nomination, Khazei bowed out of the primary race at the end of October, saying Warren had clearly “struck a chord” with citizens across the state and country.


That last part is significant, political observers said – this race has sparked major national interest, and that is showing in a surge of out-of-state campaign contributions.


“Control of the Senate is up for grabs in 2012,” said Maurice Cunningham, a political science professor at UMass-Boston. “There are only two Republican senators that are in any trouble and this is one of them.”


Other than Brown’s upset of state Attorney General Martha Coakley in a special election to replace the late Edward M. Kennedy last year, no Bay State Senate race has likely drawn as much national attention recently, Linsky said.


“I can’t think of a Senate race in Massachusetts that had more national buzz since Ed Brooke’s election to the Senate (in 1966),” said Linsky, who served as chief secretary and counsel to Gov. William Weld.


All the Senate candidates have filed itemized breakdowns of many of their contributions, which are required by federal law. While the candidates are not required to itemize contributions under $200, several detailed at least some of these donations nonetheless.


A Federal Election Commission spokeswoman also said her agency is still updating the detailed lists for the most recent quarter. The result may yet be incomplete and the listed donations do not always add up to the final fundraising totals the candidates reported. But the breakdowns still shed some light on trends in the race.


For example, while Massachusetts residents appear to have donated more to Warren than any other state, at least two-thirds of her money overall came from elsewhere, including hundreds of thousands of dollars from New York and California.


While Brown relied more on Bay State contributions recently, he too has benefited from contributions from other states. He also has pulled in more than $785,000 in donations from political action and other non-party committees since January.


The include donations from leadership PACs run by Sen. Minority Leader Mitch McConnell, R-Kentucky, and Sen. John Cornyn, R-Texas, and committees run by financial groups, high-tech and health care businesses and energy companies.


Warren thus far has received a far smaller $32,600 from PACs, including ones controlled by Sen. Majority Whip Dick Durbin, D-Ill., Sen. Majority Leader Harry Reid, D-Nevada, the United Steelworkers union.


Cunningham said other Democrats have little chances of defeating Warren as she leads the fundraising race.


“I don’t want to be unkind, but it’s a vanity candidacy to stay in,” he said.


After the primary, it’s going to be a “knock-down, drag-out battle all the way to November,” Cunningham said, with plenty of spending by both sides.


“This will top everything,” he said of high-cost races in the Bay State.


(David Riley can be reached at 508-626-3919 or driley@wickedlocal.com.)