Faced with a deeply disillusioned electorate and sluggish economy, President Obama is hanging his re-election chances on an aggressive grassroots ground campaign in swing states, and a mountain of cash to bankroll attacks on his future Republican opponent over the air.

Over the past six months, the Obama campaign’s state-level operations have blossomed, re-commissioning offices and volunteer networks kept warm by Organizing for America since 2008 while adding new outreach centers to help raise the president’s profile on the ground.

Obama now has campaign offices in all 50 states, opening on average three new field offices each week, said campaign manager Jim Messina.  State volunteers threw open the doors to dozens more over the weekend, from Michigan to New Hampshire, in a coordinated push exactly one year to Election Day.

“We have to ramp up our work now to create the kind of campaign we need to win in 2012,” Obama national field director Jeremy Bird wrote in an email to supporters last week.

Where the campaign is ramping up underscores the Obama team’s electoral strategy, which has aimed to broaden the pool of Obama voters, particularly in historically red states that have turned purple with recent demographic shifts.

In 2008, Obama flipped nine states that John Kerry lost to George W. Bush in 2004 — Florida, Ohio, North Carolina, Virginia, Indiana, Colorado, Iowa, New Mexico and Nevada.  Top Democrats believe he has a shot at holding all but Indiana in 2012, and possibly add Georgia or Arizona, where Hispanic and African-American voters could tip the scale.

But those battlegrounds are more hotly contested now than they were four years ago, with a recent Gallup poll showing Obama in a dead heat with Romney in a hypothetical match-up in many swing states and enthusiasm among Democratic voters dramatically down.

Between June and August, Obama opened a slew of new offices in conservative states, including two each in Phoenix and Tucson, Ariz.; one in Anchorage, Alaska; Boise, Idaho; Austin, Texas; Little Rock, Ark.; Missoula, Mont.; and Jackson, Miss., campaign finance records show.  The campaign also rented space in liberal strongholds like Los Angeles, San Francisco and Miami Beach.

In Iowa, the state that ignited Obama’s candidacy in 2008, organizers opened eight offices with much fanfare in September, while in New Hampshire, staffers announced the opening of a second outpost last week.  Obama has offices in Concord and Portsmouth.

“We’re established in Florida,” said a Democratic official supporting the Obama campaign.  ”We’ve always had the organizing infrastructure to let people know we’re here and we’re reminding people now.”

Obama has at least four offices in Florida, in Jacksonville, Miami, Tampa and Orlando, the official said.

“You all are going to be seeing an awful lot of me, because the states I am going to be concentrating on are Pennsylvania, Ohio, Florida, New Hampshire and Iowa, and I am going to be here a lot, so I am looking forward to working with you all,” Biden told the Florida Democratic Party convention last week.

“We plan on winning Florida. We can’t win without Florida,” he said.

The campaign is also expanding across mid-Atlantic states, from Pennsylvania to South Carolina, and will launch a targeted effort in the all-important Ohio, one of the keys to Obama’s victory four years ago.

“The infrastructure in Ohio has been in place under OFA since 2008 to keep our volunteers motivated and active,” said Jessica Kershaw, the Obama for America spokeswoman in Ohio.

Ohio Democrats say most of those activities have been run out of the state party offices, but now staff will open Obama campaign outposts in a region south of Columbus late next week, then in other locations in the northwest part of the state and in Columbus.

Filling the new offices around the country is an army of paid staff and strategists, including social media experts to corral what have become an army of volunteers – more than 1 million nationwide.

Obama for America nearly doubled the size of its staff on payroll over the summer, growing from 168 employees in July to 327 as of Sept. 30, according to the campaign’s third quarter financial report.

But perhaps more important than boots on the ground will be campaign cash Obama will use to put ads on the air. The president has raised more than $88 million for his re-election through September, slightly ahead of the record-setting pace he set four years ago and quadruple the cash-on-hand of Republican frontrunner Mitt Romney.

On Sunday, Obama’s surrogates fanned out across the states to keep that fundraising apace, holding events in eight major cities to gather cash on the one-year milestone before the election.