Republicans and Democrats are placing millions of dollars in risky bets on television advertisements that could ultimately determine which side controls the Senate next year.

Advertising data compiled by buyers closely monitoring the market shows the stark contrast in spending priorities.

ADVERTISEMENT

The NRSC spent almost $31 million on races in nine states between August and September. The Democratic Senatorial Campaign Committee spent just over $13 million during the same period, in seven states.

Beginning in October, the disparity has been reversed. The NRSC has reserved just $10 million in airtime in ten states. The DSCC has purchased or reserved almost $44 million in eleven states.

There’s logic behind both approaches, and the two parties are each seeing their countering strategies bear fruit.

The National Republican Senatorial Committee funded early ads in Indiana, where former Sen. Evan Bayh (D) held a big lead over Rep. Todd Young Todd Christopher YoungSenate GOP eyes early exit Why the US should rely more on strategy, not sanctions Davis: The Hall of Shame for GOP senators who remain silent on Donald Trump MORE (R); Bayh’s lead has shrunk to single digits amid questions about his residency and his post-Senate career on corporate boards.

Republicans spent more than $13 million in Ohio to help Sen. Rob Portman Robert (Rob) Jones PortmanMcConnell locks down key GOP votes in Supreme Court fight Romney undecided on authorizing subpoenas for GOP Obama-era probes Congress needs to prioritize government digital service delivery MORE (R) build a lead so large that Democrats have all but abandoned their nominee, former Gov. Ted Strickland (D).

On the Democratic side, waiting to advertise has given the party the chance to spend money in late-breaking states like Missouri and North Carolina, states where Donald Trump Donald John TrumpOmar fires back at Trump over rally remarks: 'This is my country' Pelosi: Trump hurrying to fill SCOTUS seat so he can repeal ObamaCare Trump mocks Biden appearance, mask use ahead of first debate MORE’s intemperate remarks and well-run Democratic campaigns have moved poll numbers against Republican incumbents.

On Thursday, Senate Majority PAC backing Democrats bought $2 million in new advertisements in North Carolina.

“While Republicans have worked nonstop since day one of this campaign to build nimble, data-driven campaigns, Democrats have relied on political gravity from the presidential race to carry them across the finish line,” NRSC spokeswoman Andrea Bozek said in an email.

A DSCC spokeswoman declined to comment on their ad buying strategy.

Several Republican strategists with knowledge of the NRSC’s plans said Ward Baker, the committee’s executive director, made clear he wanted to use party funds to advertise early, as races were only beginning to develop. Baker told consulting firms bidding for the NRSC’s business he wanted to spend money before the airwaves were crowded with messages from other outside groups.

“They made a conscious decision. Ward’s worldview is early money is better,” one strategist who pitched the NRSC said.

The huge Democratic advantage in the remaining four weeks before Election Day has been mitigated, to a degree, by outside spending. Republican-aligned outside groups including the Senate Leadership Fund, One Nation and Freedom Partners are spending nearly $45 million on Senate races in October and November. The Senate Majority PAC, the largest group backing Democratic candidates, will spend $23 million over the last two months.

But that still leaves Democrats with an advantage in the final weeks. The DSCC and Senate Majority PAC are spending a total of $67 million on Senate races between October and November. The NRSC and its outside allies are spending $55 million on the same races.

That total doesn’t include other Democratic-friendly groups, which are carefully picking their battles. Since the beginning of October, AFSCME and SEIU have been purchasing ads in North Carolina, while the League of Conservation Voters and Planned Parenthood Action Fund are starting to invest in Nevada.

That Democratic advantage has some GOP strategists worried.

“Republicans have put their Senate candidates in a great position with an early spending advantage,” said Carl Forti, a veteran Republican ad buyer. But, he warned: “Getting out-bought in October by close to $20 million is a major problem for Republican Senate candidates, especially with the volatile nature of the presidential race.”

Over the last several weeks, Democrats have purchased significantly more advertising dollars than Republicans in three states: North Carolina, where Sen. Richard Burr Richard Mauze BurrRep. Mark Walker says he's been contacted about Liberty University vacancy Overnight Defense: Trump rejects major cut to military health care | Senate report says Trump campaign's Russia contacts posed 'grave' threat Senate report describes closer ties between 2016 Trump campaign, Russia MORE (R) is running virtually even with former state Rep. Deborah Ross (D); Nevada, where Rep. Joe Heck (R) faces fallout after rescinding his endorsement of Trump in his battle against former Attorney General Catherine Cortez Masto (D); and Pennsylvania, where Sen. Pat Toomey (R) and former state official Katie McGinty (D) are running neck and neck.

Democratic groups are also spending $1.3 million more than Republican groups in Florida, though Sen. Marco Rubio Marco Antonio RubioOvernight Defense: Pentagon redirects pandemic funding to defense contractors | US planning for full Afghanistan withdrawal by May | Anti-Trump GOP group puts ads in military papers Democrats step up hardball tactics as Supreme Court fight heats up Press: Notorious RBG vs Notorious GOP MORE (R) is vastly outspending Rep. Patrick Murphy (D) on television. Polls show Rubio ahead by a small margin.

Republicans are spending significantly more than Democrats in Missouri, where polls show Sen. Roy Blunt Roy Dean BluntSocial media platforms put muscle into National Voter Registration Day Senate GOP faces pivotal moment on pick for Supreme Court This week: Supreme Court fight over Ginsburg's seat upends Congress's agenda MORE (R) locked in a surprisingly close race with Secretary of State Jason Kander (D). The GOP has booked $3 million more in television time on Blunt’s behalf over the last two months than have Democrats and their allies.