For Mitt Romney, the magic number is $158 million. That's how much he'll have to outraise President Barack Obama over the last four months of the campaign to surpass the president, the record holder for campaign fundraising.

Obama's advantage has been lost in media reports highighting the Republican nominee's $106 million June haul. Even Obama's campaign, including the president himself, has downplayed its financial advantage when it warns of being outspent by Romney and the Republican National Committee. For that to happen, Romney would have to best Obama by $39.5 million a month for each of the last four months of the campaign, which is $5 million more than the advantage Romney had in June.

An analysis of Federal Election Commission (FEC) disclosure reports starting when Obama and Romney formally disclosed their candidacies running through the end of May 2012, and adding in totals the campaigns have announced for June, shows that Obama and his affiliated groups have raised $552.5 million, compared to Romney's $394.9 million. For Obama, the total includes money from the president's campaign committee (Obama for America), the Democratic National Committee and two joint fundraising committees — Obama Victory 2012 and Swing State Victory Fund. For Romney, the figure includes money from the campaign, the Republican National Committee and Romney Victory Inc., the joint fundraising committee Romney formed in April.

The timeline of this fundraising is charted below:

To date, the incumbent has surpassed — in some cases far exceeded — the challenger in every category of political money that candidates and the parties directly control. Even independent, outside groups that support Obama have spent $7.6 millon more attacking Romney than Romney's surrogates have spent going after Obama.

Breaking down the numbers

Through May, Obama's campaign committee has raised more than $257 million — either by Obama for America ($198.7 million), or through transfers from the Obama Victory Fund 2012 ($58.9 million). Romney has raised $119 million, with $112 million of that donated to his campaign, Romney for President, and $7 million from transfers made by Romney Victory, Inc., his joint fundraising committee.

Obama's campaign has bested Romney's campaign every month this year and every quarter in 2011 (when both Obama's and Romney's campaigns reported quarterly). The closest Romney came to Obama's fundraising total was in January 2012, when Obama topped him by $5 million. Over the last three months for which FEC disclosures have been filed — March, April and May — Obama's campaign has bested Romney's by an average of $17 million a month. 

The Democratic National Committee (DNC) also leads the Republican National Committee (RNC) — $184 million to $159 million. When the GOP bested the Democrats in May by $14 million, it was the only third time in the last 17 months it had done so.

The lopsided money chase isn't necessarily surprising, considering that Obama began raising money for his campaign and the DNC through the joint fundraising committee in April 2011 (he raised $7 million for the DNC that month). Romney, on the other hand, first had to secure his party's nomination. That meant he started the joint fundraising committee one year later, in April 2012, by which time Obama Victory Fund 2012 had raised $144 million, the bulk of which was split up between his campaign and the DNC.

Overall, FEC reports show Obama and the DNC benefitng from some $188 million that he's amassed through his joint fundraising committees, including $3 million through the Swing State Victory Fund, which distributed money to the federal committees of battleground state Democratic parties. 

Figuring the same number out for Romney is trickier, because Romney Victory Inc. — the Republican presidential joint fundraising committee — has chosen to disclose information to the FEC on a quarterly basis. While Romney Victory won't file its first report until mid-July, reports from Romney's campaign and the RNC touting their joint fundraising have inlcuded figures on their fundraising. For example, Romney's joint fundraising committee, his campaign and the RNC pulled in $76.8 million in May. The RNC raised $34.3 million that month, and Romney's campaign pulled in $16 million, so the joint fundraising committee must rave raised $26.5 million.

In April, according to media accounts (again, we don't have disclosures from Romney's joint fundraising committee), when the RNC raised $11.4 million and Romney's campaign reported another $11.4 million, the total take — including the undisclosed sum from the joint fundraising committee — was $40.1 million. Therefore, we can calculate that Romney Victory Inc. might have pulled in around $17.3 million.

The media reporsts suggest Romney's joint fundraising committee has taken in $43.8 million in its first two months of existence — far less than the $188 million Obama has raised.

History's guidance

Obama, like his predecessor George W. Bush in 2003 and 2004, has been on a fundraising marathon. Romney, like Bush's opponent, Sen. John Kerry (D-Mass.), is sprinting to catch up. In 2003, Bush raised $132 million for his campaign and the RNC took in $106 million. Kerry raised $19.6 million, while the DNC raised about $43 million.

That 2004 race shows how hard it is for a challenger to beat an incumbent's fundraising head start. After securing the Democratic nomination in early March, Kerry went on a fundraising tear: the DNC, Kerry's campaign and his joint fundraising committee outraised the mighty Bush money juggernaut by an average of $22 million a month, capped by a $35 million advantage in July. Still, in the end, Bush outraised Kerry by about $27 million, largely on the strength of his 2003 fundraising efforts.

Like any incumbent president who does not face a challenger in the primaries, Obama has been free to raise money and build an organization focused on winning the one election in November. Romney, on the other hand, had a lengthy primary battle, and faces some well-publicized challenges in trying to unite his party.

There is no guarantee he will do so. From the perspective of fundraising, that means he may not be able to attract the donors who gave to Newt Gingrich, Rick Perry, Rick Santorum or the other GOP presidential hopefuls. Romney's reported June fundraising totals suggest he may be succeeding.

On the other hand, there may be bigger signs of trouble in Romney's small donor gap. As in his 2008 run, Romney has had difficulty raising money from donors who contribute less than $200; they provided eight percent of his total fundraising back then. In the current election cycle, 13 percent, or $15.6 million, of Romney's contributions have come from small donors. By comparison, Obama has raised 43 percent or $109.5 milion of his campaign warchest from small donors. Previous Republican nominees, including both George W. Bush (26%) and John McCain (21%), enjoyed higher levels of financial support from the Republican grassroots during their primaries than Romney.

Romney's reliance on large donors has its perils — a smaller base of large donors who max out can no longer contribute to the candidate, whereas a large base of small donors can be asked to contribute repeatedly. 

Unlimited money the equalizer?

Of course, the big change this year is the proliferation of outside groups, which can raise unlimited money. Will all the fundraising by Restore Our Future, American Crossroads, Crossroads GPS and other groups end up outgunning Obama? It's not clear that they will.

First, consider that conservative and Republican leaning super PACs and nonprofits aren't spending only to defeat Obama; sometimes they're spending to foil each other. The American Action Network faced off against the Club for Growth in last month's Republican Senate primary. Richard Mourdock, backed by the Club for Growth, defeated veteran Sen. Richard Lugar (R-Ind), who had the support of American Action Network.

Second, when it comes to spending on the presidential race (as opposed to raising money), it's hard to discern a clear pattern: Some outside groups have so far spent $10.8 million opposing Barack Obama, while others have spent $23 million opposing Mitt Romney, including $13.5 from Priorities USA Action, $1.6 million from Planned Parenthood, and $1.5 million from the AFL-CIO. To date, the outside spending hasn't been enough to offset the other fundraising advantages Obama has. Additionally, Obama has benefitted from the anti-Romney spending during the GOP primary. Republican donors — including casino mogul Sheldon Adelson — paid for the first effective Bain Capital attacks run against Romney. Obama has since picked up and refined that very theme.

Third, the "noncommittee" committees — the 501(c)4s and 501(c)5s like, respectively, the Planned Parenthood Action Fund and the AFL-CIO — don't have to dlsclose how much money they have in their war chests, ready to deploy. While Crossroads GPS, the Koch Brothers and others might have bulging bank balances burning holes in their political pockets, so too do unions like AFSCME and SEIU, and social welfare organizations like the League of Conservations Voters Fund and Patriot Majority USA.

Advantages of complete control

Meanwhile, those running super PACs don't necessarily have the same agenda as the presidential candidates. If Karl Rove and his colleagues at Crossroads GPS conclude that Romney isn't close enough in the polls to pull out a win, they could decide to target their money to Senate candidates or on close House races instead. Romney doesn't control the money the outside groups have amassed, and those who do control it aren't necessarily Romney enthusiasts — with Restore Our Future being a notable exception.

The American Action Network, a well-funded Republican nonprofit organization, recently announced a $10 million effort to support Republican House candidates in states that lack strong local Republican organizations. That's $10 million that won't be directed to trying to elect Romney.

Even assuming that every conservatively-inclined super PAC is pro-Romney, they're still no substitute for a candidate with money in his own accounts. In the summer of 2004, when the Swift Boat Vet ads started, Kerry's campaign wanted the 527s (that year's version of super PACs) to rebut the ads. Harold Ickes, who was as much of an insider as any of the current crop of super PAC major domos — he was on the DNC's steering committee at the same time he was running one of the biggest 527s — felt like it was the Kerry campaign's job to rebut the charges. As a result, the Swift Boat Vet ads ran with no rebuttal, perhaps sinking Kerry's election.

In an analysis of the 2004 election, the Washington Post concluded, "A supposed strategic advantage for the Democrats — massive support from well-endowed independent groups — turned out to have an inherent flaw: The groups' legally required independence left them with a message out of harmony with the Kerry campaign."

The Post went on to note that, "A large part of Bush's advantage derived from being an incumbent who did not face a challenger from his party. He also benefited from the experience and continuity of a campaign hierarchy, based on a corporate model, that had essentially stayed intact since Bush's 1998 reelection race for Texas governor."

Those are the same advantages that the current incumbent enjoys. And just as the Swift Boat Vet ads attacked one of Kerry's supposed strengths — his Vietnam service record — without a response from the candidate or the 527s supporting him, the Obama campaign is attacking Romney's key qualification, his record turning companies around at Bain Capital. Though factcheckers have criticized the ads and Romney has denounced them, Restore Our Future, which had $8.4 million cash on hand at the end of May, has yet to rebut them.