WASHINGTON — (CNN) Donald Trump, who overcame an onslaught of negative advertising to clinch the GOP nomination, recently turned to supporters at a rally for advice.

“Do ads work anymore?” he asked.

If they do, Trump is getting left behind.

The presumptive GOP nominee is being massively outspent on television airwaves: Between Tuesday and Election Day, Trump has reserved zero dollars in television advertising, compared to $117 million from Hillary Clinton and her allies, according to data from the ad tracking firm Kantar Media/CMAG.

Compared to Team Clinton’s spending, the buys from pro-Trump groups are a drop in the bucket.

Among the pro-Clinton spots is one that hammers Trump as “too dangerous for America.”

That messaging, if it sticks, could pose yet another hurdle for Trump, whose campaign is in turmoil amid criticism that it has a barely functioning infrastructure.

Trump, who on Monday fired his campaign manager, Corey Lewandowski, also hasn’t built other common elements of a national campaign, such as a fundraising base or an extensive network of field staff.

The pro-Clinton effort looks like a traditional ad-buying campaign, with a mix of $21 million from her campaign and major buys from Priorities USA Action, the main super PAC supporting her bid.

Clinton and the super PAC have already run $12 million of television advertising in eight battleground states since she clinched the nomination earlier this month, according to the ad tracker.

Trump, on the other hand, hasn’t bought any television advertising since early May, when he spent a small amount for ads in Indiana and Nebraska.

One of the super PACs supporting his candidacy joined the ring on Monday, announcing a $700,000 buy contrasting the two candidates’ handling of national security threats.

Another group recently spent $1.7 million on an ad critical of Clinton. That buy was on national cable and didn’t focus on the key states that typically decide the November election.

The difference in what viewers see is stark: In the first week of the general election, Clinton and her super PAC ran nearly 4,000 more spots on broadcast and national cable TV than Trump and his allies, according to the Kantar Media data.

Trump won in the primaries despite being outspent.

In several states, he only began advertising with days left before voters cast their ballots.

At one point in the primary, Trump quipped he started advertising on television “because I feel guilty” that others were spending heavily, yet were still out-polled by him.

Regardless of how much he invests in his own advertising, Trump can be expected to respond to Clinton’s ads.

“Believe me folks, they’re false ads,” he recently told supporters in California. “They are so false. Ah, some of them aren’t so false. Mostly.”