HARRISBURG, Pa. — A massive influx of advertising dollars is currently targeting voters in key regions such as the Rust Belt, Rocky Mountains, and the American Southwest as the major political parties prepare for a fierce battle over Senate control.

In just three crucial races—Ohio, Pennsylvania, and Montana—expenditures are expected to surpass $1 billion by the time polls close on November 5.

The Ohio contest is on track to potentially set a new spending record for Senate races. Meanwhile, the Montana race is poised to become the most expensive on a per-vote basis ever recorded. Additionally, as the election nears, Democrats are significantly increasing their financial backing in Texas, a Republican stronghold, where they aim to unseat two-term conservative Senator Ted Cruz—a shift that could help them maintain their majority in the Senate.

To regain control, Republicans must gain two seats, one of which—West Virginia—is nearly secured for the GOP. However, other seats are more uncertain, creating a competitive landscape.

For Democrats, the challenging dynamics of the election cycle entail the defense of eight seats across tough states. Significant losses among established incumbents could spell disastrous outcomes for the party in areas traditionally dominated by Republicans.

This election also serves as a litmus test for both parties in key battleground states such as Wisconsin, Michigan, and Pennsylvania, all of which form part of the so-called Blue Wall thanks to their historical tendency to lean Democratic. Gains for Republicans in these areas could drastically reshape the Senate map.

Overall, political ad tracking firm AdImpact has projected that spending on Senate race advertising will exceed $2.5 billion during this two-year campaign cycle, slightly surpassing total expenditures from 2022.

A breakdown of the expected spending reveals about $500 million in Ohio, roughly $340 million in Pennsylvania, and around $280 million in Montana, which has a population of just 1.1 million—significantly smaller than either Ohio or Pennsylvania. The most expensive prior Senate race was Democrat John Ossoff’s victory in a Georgia contest that required a runoff in 2021, determining Senate control, as reported by the campaign finance-tracking organization Open Secrets.

Campaign strategists observe that Republican presidential candidate Donald Trump holds a stronger position in the polls than the party’s Senate nominees in battleground states. Conversely, Democratic contenders are faring better than their presidential nominee, Kamala Harris—indicating a possibility for ticket-splitting voters who might support Trump but not the Republican Senate candidates.

Instances of this behavior are uncommon. For instance, in Maine during 2020, voters favored Democrat Joe Biden for president while re-electing Republican Senator Susan Collins.

Republican strategists anticipate significant backing from the party’s super PACs through Election Day in seven states where Democrats are defending their Senate seats, such as Michigan, Montana, Ohio, Pennsylvania, and Wisconsin—where competitive polling is evident—and in Nevada and Arizona, where strong early voting numbers have encouraged Republican optimism.

The GOP appears confident about capturing the seat in staunchly Republican Montana, with Tim Sheehy challenging third-term Democrat Jon Tester, as well as in Ohio where Bernie Moreno is contesting against third-term Democrat Sherrod Brown.

Torunn Sinclair, representing Republican-aligned super PACs, mentioned that American Crossroads is reallocating $2.8 million out of Montana, while funneling several million additional dollars into Pennsylvania. There, Republican candidate David McCormick seeks to upset three-term Democratic Senator Bob Casey in a closely monitored race.

McCormick, a former hedge fund CEO, has used two debates to emphasize that Casey is likely to align decisively with the Biden-Harris administration’s agenda. Recently, Casey’s team released an advertisement in conservative regions reinforcing his “greedflation” legislation aimed at curbing price-gouging, also highlighting that he has “bucked Biden” to support fracking and “sided with Trump” on tariff matters.

Republicans argue that Casey’s advertisement featuring Trump mirrors a campaign strategy seen by Senator Tammy Baldwin of Wisconsin, revealing a shared necessity among Democrats to defend against the vulnerabilities linked to Harris in their states. “They’re aiming to attract enough Trump voters to secure victory,” Sinclair noted.

Nevertheless, Casey employed a similar advertising strategy during the 2018 midterms when he won decisively, even though that campaign did not reference Trump. Casey’s campaign insists he has consistently distanced himself from the Democratic mainstream by opposing free trade deals and endorsing fossil fuel initiatives.

On the flip side, Democrats believe they are creating competitive races in two traditionally Republican areas: Texas and Nebraska. Wiping out incumbent Republicans in one or both states could significantly bolster the Democrats’ chances of maintaining at least a 50-50 Senate split, particularly if they face losses in Montana or Ohio.

In Texas, Congressman Colin Allred, who previously played professional football, has demonstrated a talent for garnering small-dollar donations against incumbent Republican Senator Ted Cruz. He has outpaced all Senate candidates, save for Tester and Brown, in fundraising.

The advertising funding advantage for Allred stands at 3-to-2 according to AdImpact, with the Democratic-aligned Senate Majority PAC launching a fresh seven-figure digital advertising campaign alongside a $5 million television advertising effort targeting Cruz based on critical issues such as abortion rights.

Additionally, Democrats are keen on harnessing the impact of a rally in Houston, featuring Harris, Allred, and Beyoncé, which they hope will enhance Black voter turnout.

In Nebraska, independent candidate Dan Osborn—who has distinct tattoos and champions abortion rights—seems to be unifying Democratic and independent support while making strides with some Republicans, as noted by Democratic strategists. Although running as an independent without clear party alignment, his campaign has gained traction due to backing from a liberal super PAC facilitating a considerable spending advantage against Republican Senator Deb Fischer.

Republicans have acknowledged the necessity to allocate unexpected funds to safeguard their incumbents’ positions, while maintaining confidence in a comfortable victory.

In Ohio, Brown’s strategy revolves around personalizing his narrative by featuring himself prominently in his advertisements, often addressing the camera directly. “I’m Sherrod Brown, and I have a question,” he states candidly, while leaning on a table reminiscent of a workshop. “Have you ever heard Bernie Moreno discuss his plans for Ohio?”

Brown appeals to potential swing voters by highlighting his commitment to fighting for workers, veterans, and partnering with law enforcement and “presidents from both parties” to advocate for the state’s best interests.

In other political scenarios, strategists predict that first-term Florida Senator Rick Scott will prevail against Democrat Debbie Mucarsel-Powell, while Democrat Angela Alsobrooks is projected to defeat former Governor Larry Hogan in deep-blue Maryland to take over a seat being vacated by Democratic Senator Ben Cardin.