Republicans are swamping House and Senate races with an unprecedented flood of late ad spending as the party tests whether hundreds of millions of dollars can buy it some reprieve from the eroding political environment that’s threatening longtime Republican states and districts. Since the start of September, Republicans have made more than $700 million worth of new advertising bookings in congressional races alone, according to an NBC News analysis of data from AdImpact, a political ad-tracking firm. That’s new money on top of what had already been committed to those races in ad reservations made over the summer.

By comparison, Democrats booked more than $430 million in new ad reservations across those races last month. The disparity is greatest in the battle for the Senate majority, where almost 7 of every 10 newly booked advertising dollars are coming from Republicans. That’s led by a massive, late investment in the Senate race in Texas, where Democrat James Talarico is threatening a longtime Republican seat and the GOP has poured in almost $150 million in new ad dollars to back up its nominee, Ken Paxton.

The gap is smaller in the House, where a bit less than 6 in 10 of those new ad dollars are coming from the GOP. Democrats still have a number of advantages in their corner, including President Donald Trump and his party’s eroding standing among voters, Democrats’ own well-funded candidates, and help from outside groups. Candidates can take advantage of a rule that allows them to buy television ads at cheaper rates than outside groups, too. But the color of the outside money flood shows how Republicans, increasingly on defense in both the House and the Senate, are able to lean on their financial advantage in hope of defying political gravity, as party bastions like Texas and even Kansas look more competitive than usual.

“With the environment not on our side and an incumbent presidency, the three things we have going for us are good candidates, a good map and a lot more money than they do,” said a Republican strategist involved in Senate races. Everything about the late flood of ad spending is bigger in Texas, where a new group called Texas PAC has booked more than $115 million over the last month alone aimed at boosting Paxton, the state attorney general. Democrats haven’t won a statewide election in Texas in more than 30 years.

But because Republicans are spending largely through outside groups, they have to pay a premium on the rates for each ad, while Talarico’s flush campaign is able to capitalize on those lower candidate ad rates. That means the spending disparity is greater than the actual number of ad airings or their reach. Senate races in Ohio and Michigan also drew more than $75 million in new ad dollars in September, mostly from Republican-aligned groups. They include a super PAC funded by cryptocurrency interests, Trump’s aligned super PACs and other groups aligned with the national party or Senate Republican leadership.

Again, both states have Democratic candidates — former Sen. Sherrod Brown in Ohio and former county health official Abdul El-Sayed in Michigan — who have been spending significant money on their advertising campaigns. No Going Back PAC and Safety and Affordability PAC have made more than $150 million in new ad bookings since the start of September across dozens of races. While the groups haven’t confirmed where they’ve gotten their war chest from, The New York Times recently confirmed that MAGA Inc., Trump’s main super PAC, is primarily funding the effort with the hundreds of millions of dollars it has banked over the last few years.

Sen. Tim Scott of South Carolina, chair of the Senate GOP’s campaign arm, touted the party’s spending advantage as key to helping Republicans hold on to their majority and credited Trump’s deep-pocketed political operation with ensuring the flood of cash continues. Scott told reporters that he met last week with Trump’s chief of staff, Susie Wiles, and that the message from Wiles was “money will not be our problem.”“That’s exciting news to me,” Scott said, adding later, “Knowing that they are going to invest completely in these races is incredibly helpful, because cash is king.”

“We finally find ourselves at a cash advantage because of MAGA Inc. It’s a powerful tool that is providing us with the firepower necessary to really share our message,” he said. Democrats take some solace in where the new spending is going. The vast majority is plowing into states and seats Trump carried in 2024, including congressional districts Trump would have won by double digits that year, like North Carolina’s 1st District, Texas’ 35th District and Alaska’s at-large congressional district.

The money is also going to races in which Republicans felt comfortable until recently, like the Senate race in Kansas, where the top Senate Republican super PAC just reallocated millions initially meant to be spent in North Carolina. “The money is not because there is this swell of Republican momentum; the money is because of a swell of Republican panic,” said Lauren French, the communications director at Senate Majority PAC, the super PAC aligned with Senate Democratic leadership. “Voters don’t like anything they are selling — that includes the message, the candidates and the president.”

Meredith Kelly, a longtime Democratic strategist who works on House and Senate races, said, “When you are defending in such deep-red territory, the technical term for that is: ‘You’re f---ed.’”“Republicans, if they have one advantage, it’s that they have more money, and they are putting that money to the test right now post-Labor Day,” Kelly added.

“However, the big question is: Is that money enough to counteract the fact that Donald Trump’s coalition is falling apart?”Still, Democrats are uncomfortable watching their party get outspent to such a degree. “It’s a huge problem, and it will be an ongoing problem, and you see all the lists of high-value donors for both parties and we get swamped every time,” Kelly said. “It creates such an initial advantage for the Republicans that we have to close the gap on in a variety of ways — candidate money, better message, better candidates. We are setting ourselves up for an uphill battle every single time because of the Republican donor strength in terms of the billionaire class.”