This article is from the archive of our partner National Journal

A restless electorate and a target-rich map have the GOP on the cusp of winning the Senate majority. But with fewer than 40 days until November, Republican campaigns are suddenly confronting a problem that undermines high hopes of victory: a sudden and serious lack of cash.

GOP campaigns, political committees, and—above all—the party's outside groups are scrambling to raise money, worried that Democrats and their allied groups are poised to heavily outspend them on TV ads in the final weeks before Election Day. Concerns run deepest about October, when Democratic groups are on track to pour millions of dollars into a handful of races that will determine which party controls the Senate. In some of those same races, Republicans have reserved little or no airtime.

The disparity has led to mounting frustration among political operatives running Republican campaigns. And they are issuing a blunt warning: In a year with a half-dozen tight Senate contests, the party could easily squander most of them.

"I am worried about it for the first time in a long time," said Rob Jesmer, who ran the National Republican Senatorial Committee in 2012 and 2010 and continues to work on behalf of Senate campaigns now. "I think in some of these places, it could be the determining factor."

The party, Jesmer says, still has a good chance of taking the Senate from Democrats. "But if we don't, the story is going to be that outside money saved these guys."

Republican complaints about a lack of late-cycle funding are being met with guffaws from Democrats, who point out—rightly—that the GOP benefitted from an unprecedented early spending blitz from the conservative group Americans for Prosperity. The Koch brothers-backed organization spent upwards of $40 million on a handful of important Senate races, and that likely means Republicans have already spent far more in most battlegrounds.

Yet still, the early deluge of pro-GOP spending has now been matched and, in some places, exceeded by Democrats, leaving Republicans struggling to keep up.

Why outside groups are turning off the spigot now is a mystery to GOP strategists. Some say donors were unhappy with the performance of outside groups in 2012, have viewed the NRSC skeptically for back-to-back cycles, or are afraid of receiving the same treatment that befell Charles and David Koch at the hands of Majority Leader Harry Reid, who relentlessly and publicly maligned the brothers this year.

Indeed, the political empire founded by the duo, for all of its early spending, has not been the source of infinite cash that some GOP operatives had once hoped. They appear content instead to build a small army of paid staffers and volunteers in swing states such as North Carolina.

Regardless, the problem for Republicans in races that could still go either way is about to become more pronounced as the final month of the campaign season begins.

Democratic and Republican sources tracking ad buys in Senate races describe a landscape that, for now, shows big gaps in Republican spending. In Colorado, for instance, Crossroads GPS, the nonprofit arm of the Karl Rove-aligned American Crossroads, has spent or is slated to spend millions of dollars in on-air spots from mid-September to mid-October. But it hasn't reserved so much as a dime in airtime during the race's final two weeks.

Two other groups—Freedom Partners, another organization affiliated with the Koch brothers, and the NRSC—each have modest buys worth less than $1 million declared for the back half of October. And their combined totals barely match what the Democratic Senatorial Campaign Committee is scheduled to spend in a single week.

In fact, the DSCC and the Senate Majority PAC, a group staffed by close allies of Reid, have reserved more than $4.5 million combined in the season's final weeks.

The gaps extend to other battlegrounds. One official at the NRSC who tracks media buys said Democrats and their allies have spent or already reserved $23 million more in TV ads between Sept. 1 and Election Day in seven Senate races—Colorado, Iowa, Michigan, Minnesota, North Carolina, New Hampshire, and Virginia. (Virginia and Minnesota are both considered fringe opportunities for the GOP.)

Exacerbating the problem for the GOP is that in most races, an incumbent-heavy field of Democrats with vast fundraising networks has raised significantly more cash than GOP hopefuls, some of whom had to invest heavily in a primary before even reaching the general election.

American Crossroads, the NRSC, and others can still reserve additional airtime, and in some states, it's almost certain they will. But buying TV ads so close to Election Day is costly, inefficient, and can make it hard to coordinate spending with other groups. It's why Democrats, led by the Senate Majority PAC and DSCC, reserved airtime months ago.

It's impossible to determine how much extra a group like Crossroads, which as an independent group already pays a higher rate than party committees or candidates, will pay for buying late, said Elizabeth Wilner, senior vice president of Kantar Media Ad Intelligence. But the difference can be significant.

"Placing a late buy can cost exponentially more than an advocacy group who placed a buy early," she said.

Republicans have been vocal about their money problems of late. Rove wrote a column in The Wall Street Journal last week sounding the alarm and issued a similar worry during an appearance on Fox News Sunday. The NRSC, in a daily email to reporters, highlighted a section of the Wall Street Journal editorial that declared that the "untold story of this campaign is that Democrats are trouncing Republicans on fundraising."

The protestations are in part a transparent effort to rally the donor base. But at some level, they're also an early attempt from Republican strategists to assign blame in case the GOP doesn't gain the six seats necessary in November to take the Senate. In fact, it's why both parties are arguing over which side is spending more than the other in Senate races.

But for whatever posturing the GOP is making, most strategists insist the concern is real. And, they argue, it could easily make the difference between winning and losing.

"Late advertising is going to matter," said Brad Todd, a GOP strategist working on a handful of important Senate races. "I think there is concern among a lot of Republicans that our donors have not quite realized the opportunity out in front of them."

This article is from the archive of our partner National Journal.

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.