President Obama’s decision to begin his 2012 reelection campaign Monday is about much more than raising money. It is an acknowledgment by his team that the grass-roots army that helped propel Obama to the White House needs repair and rejuvenation.

That corps of volunteers defined the character and personality of Obama’s first run for the White House. His candidacy was in many ways an organic movement, which sprang to life in 2007 and gathered momentum through the course of the campaign. Since then it has atrophied.

Obama advisers know that whether he is reelected will depend on many things, some of which are out of their control. What they also know is that a victory will rely in part on their ability to reenergize those volunteers, to stitch together the unusual coalition of African Americans, Latinos, young people, women and college-educated white voters who backed Obama in 2008. That is within their control.

Monday’s headlines focused on the president’s “billion-dollar campaign” and the lengths to which campaign manager Jim Messina, among others, has begun wooing big donors and setting large fundraising targets.

The desire to start raising money early should not be underestimated. Obama was extraordinarily successful bringing in small donations in 2008. His haul via the Internet — hundreds of millions of dollars — underscored the bottom-up nature of his candidacy.

He is unlikely to match that again, which means he must raise more money the old-fashioned way — through contributions of $2,500 per donor and bundled by a massive fundraising team that already has its marching orders. That money will fund the Obama operation and the campaign’s television advertising. The president will also help raise money in larger amounts for the Democratic National Committee to fund its role in the campaign.

Money is also on the minds of Obama’s team because of what the Republicans did in the 2010 midterm campaigns. Outside conservative groups raised tens of millions of dollars for independent expenditure ads in competitive Senate and House races. They are gearing up for an even bigger push in 2012.

Four years ago, the Obama operation discouraged such independent expenditure organizations on the Democratic side, preferring to keep control of as much of the campaign message as possible. There is every indication that they have changed their minds and will welcome the creation of an organization to shoulder that responsibility for 2012 with help from close allies who worked on the 2008 campaign and later the White House.

Starting to raise money now also will preclude other Democratic organizations — the House and Senate campaign committees, for example — from soaking up all the available federally regulated money.

So, for all the obvious reasons, money was crucial in starting the campaign early.

But all anyone needs to do is read the short e-mail message and watch the two-minute video that Obama’s advisers e-mailed to supporters Monday.

“We won in 2008 largely on the strength of an energetic group of Americans out there who really were invested in this and we’re going to need that again, no question about it,” said David Axelrod, the chief strategist for the reelection campaign. “It takes time to build.”

Five people are featured in the new Obama campaign video: Ed, an older white man from North Carolina; Gladys, a Hispanic woman from Nevada; Katherine, a white woman from Colorado; Mike, a 2012 first-time voter from New York; and Alice, an African American woman from Michigan. Geographically or demographically, they are the targets for Obama’s campaign.

Without a huge turnout of minorities, another surge among voters younger than 30, and good margins among the minority of white voters who are in Obama’s coalition — particularly independents who defected between 2008 and 2010 — the president’s chances of winning could be compromised. Events might break in his favor, in which case reelection could be easier than it looks now. But no smart campaign prepares on the basis of best-case scenarios.

Geographically, every state represented by the five people in the video is a battleground, with the exception of New York, a Democratic haven. Republicans might scoff at the idea that Obama can carry North Carolina again. Colorado and Nevada could be more difficult this time, as could states not represented in the video, such as Indiana and Virginia. But Obama’s team will not start the campaign with a constricted view of the electoral map.

While Republicans are battling for their nomination, the Obama team will be building robust organizations in every one of those anticipated battleground states. It believed it could not wait longer to start that process.

Another line from the president’s e-mail to supporters is telling: “In the coming days, supporters like you will begin forging a new organization that we’ll build together in cities and towns across the country. . . . We’ll start by doing something unprecedented: coordinating millions of one-on-one conversations between supporters across every single state, reconnecting old friends, inspiring new ones to join the cause and readying ourselves for next year’s fight.”

One of the requirements Obama established at the very start of his first run for the White House was that it would be bottom-up, not top-down — a reflection of the community organizer-turned-politician.

Out of that directive, Obama’s organizers experimented with how to build an operation. The widely heralded organization in Iowa was created differently than the equally effective organization in South Carolina. For the general election, Obama’s team blended best practices. At the heart, however, remains the belief that person-to-person contact — lots of it — is the key to mobilizing voters and that no two states will be organized the same way.

That ethic continues to infuse the reelection campaign. Certainly it will be difficult to re-create the energy and excitement of 2008 because it was unique in so many ways. Beyond that, Obama has disappointed many of those early followers with his choices in office. Making them feel good about the president is another priority of the reelection team, and it is arranging listening sessions among small groups.

When Obama for America morphed into Organizing for America after the 2008 campaign, it lacked some of the bite, energy and effectiveness it once had. Obama’s political team found it much more difficult to mobilize supporters behind legislative battles or even behind 2010 Democratic candidates, particularly those who didn’t make an effort to connect with the Obama operation.

The president’s advisers know from experience how long it takes to build a 50-state army in the best of times and how much these are not the best of times. Much of what Obama’s newly minted campaign does will not be visible for many months — other than the amount of money raised during the coming quarters of the year. Nor will it be particularly glamorous.

But the Obama team considers it essential. That’s why it is starting now, even before any serious Republican candidate has announced a campaign.