By Alina Selyukh and Alexander Cohen
WASHINGTON (Reuters) - With the November 6 election just three weeks away, the presidential campaigns are kicking into high gear their efforts to galvanize grass-roots supporters and ensure Americans turn out to vote.
President Barack Obama and Republican challenger Mitt Romney have each mobilized a "ground game" that has local staff knocking on doors, making phone calls, sending mail and otherwise ensuring each campaign's message is widely spread.
With the candidates in a virtual dead heat in the polls, the campaigns are determined to reach voters who are either uninterested or overwhelmed with political rhetoric on TV and online.
Below are some highlights of what the campaigns and allies of Obama and Romney are spending, buying and doing to ensure the ground game this year works in their favor.
WHO IS BEHIND OBAMA'S AND ROMNEY'S GROUND-GAME EFFORTS?
After his historic grass-roots campaign of 2008, Obama and his team retained much of that framework, maintaining contact with former organizers, building on previously created email and mailing addresses and keeping some offices.
Thanks to its large staff and trial by fire four years ago, the Obama campaign is largely self-sustaining, although campaign officials say the Democratic National Committee has volunteers helping out of their state party offices as well.
Romney, whose failed 2008 campaign for the Republican nomination did not grow to nearly the national scope of Obama's, had to start from a smaller organizational base and develop it a lot faster. His campaign began accelerating investments in office equipment and supplies in April.
That time crunch and the tradition of close work with the national party have led to a highly coordinated effort by Romney's campaign and the Republican National Committee.
Historically, labor unions have aided Democratic turnout with their own powerful grass-roots machine. This year, they face a notably improving Republican grass-roots effort spearheaded in part by conservative and Tea Party-affiliated groups such as Americans for Prosperity, an advocacy group funded by the billionaire Koch brothers that has sponsored bus tours for paid and volunteer canvassers.
HOW MANY OFFICES AND STAFF DO THEY HAVE?
The Obama campaign is not releasing the total number of staff or offices across the country, but a count of offices listed on the campaign website puts the total at 622 in the 10 swing states - more than twice as many as the 238 maintained there by the RNC and Romney campaign.
Almost all key swing states have at least two Obama offices to one Romney/RNC office: Ohio (122-40), Florida (102-47), Wisconsin (69-25), Pennsylvania (54-24), North Carolina (53-24), Nevada (26-12), New Hampshire (22-9). The ratio is more than 4-to-1 in Colorado (61-14) and 5-to-1 in Iowa (66-13). In Virginia, Obama's advantage is 47-30.
The Obama campaign touts its immense size: The latest federal disclosures showed more than 900 people on payroll, who were paid $3.1 million in total in August. Romney's campaign had about 400 people on payroll in August, paid $3.2 million, slightly more than the total for Obama's larger staff.
In addition to campaign staff, the DNC had 292 staffers and the RNC 208. DNC staffers were paid $1 million in August, versus $846,763 for the RNC staff. A small number of staffers were paid by both the campaigns and the parties.
WHAT DO THOSE NUMBERS MEAN?
The Obama campaign says its size gives it a sheer manpower advantage, presumably reaching more potential voters.
Republicans point to notably decreased levels of excitement for the Democratic president: In 2008, Obama was welcomed as a celebrity even in the Republican stalwart state of Nebraska. In 2012, Democratic pundits worried he might not be able to fill a stadium.
Republican officials routinely point out that their smaller staff is focused on efficiently reaching big results: For instance, by the end of September, they say more than 84,000 volunteers made over 30 million voter contacts.
Obama's team has not revealed a comparable statistic, but has been reported to have more than 1.5 million active volunteers.
HOW DIFFERENT ARE REPUBLICANS' AND DEMOCRATS' APPROACHES?
Republicans traditionally are masters of direct mail outreach, which they have employed on a large scale this year. In August, for instance, the Romney campaign invested some $12 million in direct mail consulting, printing and postage, according to Federal Election Commission tallies.
The Obama campaign reported no "direct mail" spending, but spent $2.4 million on printing and postage.
Where the Obama campaign has a leg up is in its Internet get-out-the-vote outreach. In the past week, Obama's team has produced a handful of videos, some with notable actors and singers, encouraging people to visit websites set up by the campaign to help people register to vote or vote early.
Obama's campaign has also spent an outsized chunk of its political cash - almost $365,000 so far in the 2012 campaign - on text messaging, which both campaigns use to remind voters of upcoming events or donation deadlines. Filings do not show a comparable number for Romney.
The Romney campaign also has a robust digital presence, reaching people through Twitter and Facebook, but Republican officials concede they are relying largely on the traditional methods of voter contact.
(Reporting by Alina Selyukh and Alexander Cohen; Editing by Peter Cooney)