Senate Republican strategists are increasingly worried that the near absence of TV ads from Donald Trump’s campaign in key battlegrounds will do irreversible harm to already difficult races.    

In state after state with both a presidential and Senate race, Hillary Clinton and her allies are on pace to spend tens of millions of dollars more than Trump and his supporting super PACs, according to political operatives tracking the data.

Unless the GOP presidential nominee dramatically increases his spending, the gap will be downright gargantuan some places. In North Carolina, where Republican Sen. Richard M. Burr faces a tough re-election fight, Clinton and Democratic groups are on track to spend $21 million. That’s seven times more than Team Trump’s $3 million.

[Senate GOP Super PAC Makes Big Push in North Carolina]

GOP strategists say that at a time when voters are splitting their tickets less than ever, Clinton’s on-air barrage could inflict significant damage on the party’s reputation as it fights to save its slim Senate majority.  

“When Hillary is running millions and millions of dollars’ worth of ads in states like North Carolina, and Donald Trump is spending virtually nothing, that’s going to help Democrats down the ballot,” said Brian Walsh, a former top aide at the National Republican Senatorial Committee. “There’s no question it’s a big problem. I believe that if Republicans lose the Senate, the responsibility lies solely with Donald Trump.”

The criticism is just the latest complaint from Republican strategists about Trump’s unorthodox campaign. They also believe he has yet to construct a top-of-the-line field operation.

In this case, they say Trump’s on-air blackout could be worth 2 or 3 percentage points of support. That might not sound like a lot, but the party is bracing for close Senate races in Pennsylvania, New Hampshire, North Carolina, and Florida where a Trump loss by 2 or a Trump loss by 5 (to say nothing of a Trump win) could mean the difference between victory and defeat for the down-ballot candidate. 

Little criticism

And yet, to party strategists, Trump has received relatively little criticism for the harmful effect his lack of ads will have on the rest of the party’s candidates.

“For some reason, people aren’t focusing on the TV spending,” said one senior GOP strategist, granted anonymity to speak candidly. “And it’s a problem.”

The source added: “We might not see it show up in the polling for a month, but that’s why we’re pulling the fire alarm now.”

The problem is especially acute in a year when the map for the presidential race and Senate battlegrounds mostly overlaps. Clinton and Trump are battling each other most fiercely in states like Iowa, New Hampshire, Florida, Ohio, Pennsylvania, and North Carolina — each of which also has a competitive Senate race.

[Roll Call’s 2016 Election Guide: Senate]

Democrats need to net four Senate seats to retake control of the chamber if Clinton wins the presidency. They need to net five seats if Trump wins, though Senate Democratic officials say they have little chance of making much headway should Clinton lose.

In late August, Trump’s campaign announced it would spend $10 million in nine states, a small sum compared to Clinton, but a sign that the candidate who didn’t run ads during the Republican primary was finally changing his tune. The campaign certainly has the money, ending last month with nearly $100 million on hand. 

But even that splurge has vexed Republicans. Trump is spending heavily in Virginia, a state seen by many as out of reach for his campaign and one that also doesn’t feature a Senate race.

Meanwhile, he’s spending almost nothing in North Carolina, where a poll released last week from Quinnipiac University showed him trailing by 4 points. (Another survey, from Suffolk University, found him winning the state by 3 points.)

Demoralizing effect

That could have a demoralizing effect on Republican voters, especially those Clinton and her allies are targeting in their ad campaigns. Priorities USA, for instance, ran ads in August that featured a Gold Star mother criticizing Trump for how he treated the parents of a dead American soldier. 

“When you have a gold star mother in North Carolina media markets that have high veteran populations, and they’re targeting veterans, that’s going to hurt people like Richard Burr,” said the GOP source.

Republicans worry the damage might be irreversible, a repeat of how President Barack Obama’s campaign defined GOP nominee Mitt Romney early in the 2012 presidential race. Romney’s vulnerability helped Senate Democrats win a number of unexpected victories, in red states like North Dakota and Montana.

[Roll Call’s Senate Challenger Rankings: Take Two]

“The Obama team defined Romney when he didn’t have the means to answer,” said Dan Allen, a veteran GOP consultant. “There was a lingering effect of that damage down ticket throughout the fall.

“The simple truth is an attack unanswered is an attack that causes more damage” he added. “A sustained, unanswered attack even more so.” 

Not everyone shares this bleak outlook. Some strategists point out that for all of Clinton’s spending, she’s still ahead in most battleground states by only a handful of points. The race could tighten further if Trump can even come close to matching Clinton’s output on air.

A tight race is all some Republicans hope for. 

“It’s that old adage, a rising tide lifts all boats,” Walsh said. “And we need the top of the ticket to be at least competitive in all these states.”