CNN  — 

If you live in Pennsylvania and have felt like you’re seeing way too many campaign commercials for this time of year, it’s not just you.

According to data from Kantar Media, President Donald Trump and former Vice President Joe Biden have spent more money on ads in Pennsylvania than any other state, followed by Florida, Wisconsin, Michigan and Arizona — all battleground states.

It shouldn’t be surprising that a presidential campaign would spend more on ads in places with more persuadable voters, particularly Pennsylvania and Florida.

“Florida and Pennsylvania are two of the biggest prizes for either candidate and probably must-wins for both Trump and Biden,” said Nathan Gonzales, the editor of the nonpartisan “Inside Elections” and a CNN contributor. “It’s hard to replace 29 or 20 electoral votes with another state.”

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But in an election year where states not traditionally in the spotlight are now up for grabs, such as Arizona, Minnesota and Georgia, both campaigns have a bewildering number of options on where to allocate their advertising budgets.

Campaign ad spending is a constant game of one-upmanship — the Trump campaign and affiliated political action committees have already made significant investments in advertising for September – but as of the end of August, Trump and Biden each have an advertising edge in five of the the 10 biggest battleground states. Biden and affiliated outside groups have spent more than twice as much in Michigan, for instance, while Trump has outspent his Democratic rival in Georgia many times over.

One thing these 10 battleground states have in common: Trump won all but one of them in 2016.

“That’s a good example of how the race favors Biden right now,” Gonzales said. “President Trump is playing defense almost everywhere and it’s difficult for him to recreate his 2016 victory.”

This year’s playing field is hard to recognize compared to 2016, when Trump and Democratic nominee Hillary Clinton spent about $52,000 on ads in Georgia combined. This year, Trump has spent about $9.4 million so far while Biden has spent about $926,000.

In 2016, neither Trump nor Clinton bothered to pay for ads in Minnesota. So far this year, Trump has spent $2.5 million and Biden has spent $795,000.

And in the wake of Clinton’s loss of the “Rust Belt” states of Pennsylvania, Michigan, and Wisconsin, Biden’s ad wallet for these three states is open a lot wider this time. So far, Biden has spent $44 million in Pennsylvania, $27 million in Michigan and $26.1 million in Wisconsin.

On CNN’s Road to 270 interactive map, Biden would be able to secure an Electoral College victory with the states Clinton won in 2016, plus Pennsylvania, Michigan and Wisconsin. Those three states also have a history of voting for a Democrat for president, adds Gonzales.

Another difference from 2016 is that Democrats are spending considerably less on ads in Ohio.

“Ohio swung so heavily toward Trump in 2016 that Democrats aren’t banking on it coming back to them this year,” Gonzales said. “But that doesn’t mean they won’t try.”

Looking at the rest of the country, Trump has outspent his rival in national ads, red states and even blue states. Aside from the battlegrounds, in the states that voted for Trump in 2016, Biden and his affiliated PACs have been considerably less aggressive, spending $5.1 million compared to Trump’s $18.7 million.

But that’s not necessarily because the Biden campaign thinks they can’t compete in Trumpland. Most of that spending went into digital ads, which are less expensive than TV and radio commercials.

Trump and Biden spent more than $228 million combined on digital ads on Facebook and Google as of August 31 — only about $1 million behind their local broadcast TV spending and more than four times what they have spent on local cable ads.

While television and radio spending are primarily used for persuading voters, digital ads are often used to appeal to base supporters for donations and build lists of voters (think of those Facebook ads asking you to “Add your name”).

“When it comes to online advertising for a national campaign, the targeting is less revealing than the ads themselves,” said Eric Wilson, a political technologist who led the digital team for Sen. Marco Rubio’s 2016 presidential campaign.

In a non-competitive state, online ads typically emphasize email list building and fundraising, Wilson said. For example, solidly blue California has wealthy donors on both sides and ranks among the top 10 states with the most ad spending overall. In more competitive states, there’s more focus on identifying and turning out voters and volunteers.

Although it’s a different type of campaigning, it’s noteworthy that the $152.9 million Trump and his affiliated PACs have spent on digital ads is more than twice as much as Biden’s digital ad buys.

“I’ve been surprised at how little the Biden campaign is investing in online advertising,” Wilson said. And as a sitting president, Wilson added, Trump also dominates TV news coverage, which means he doesn’t have to pay for the increased exposure of TV ads like Biden.

Trump’s online ad advantage may also have something to do with his target audience.

“(Trump’s) supporters are on Facebook, the demographics of people on Facebook are well suited to their target audience, and the affordances of Facebook all lends itself well to their strategic use of the platform,” said Kathleen Searles, an associate professor of political communication at Louisiana State University. “I also think that Facebook ads generally get less scrutiny, and are not subject to the same set of regulations or norms as TV ads, so that may be part of their strategy as well.”

Most of the ad spending in the 10 battleground states has been directed towards television and radio. In Pennsylvania and Florida, the gap between Biden’s and Trump’s broadcast and digital ad spending is dramatic. In Pennsylvania, Trump spent $29.6 million on TV/radio and $3.6 million on digital. Biden spent $39.1 million on TV/radio and $4.9 million on digital.

And in Florida, Trump spent $26.5 million on TV/radio and $7 million on digital. Biden spent $34.6 million on TV/radio and $7.4 million on digital.

It would make sense to spend the most on persuadable TV ads in the states with the most persuadable voters. That TV and radio ads are more expensive may be precisely the point of breaking the bank in states like Pennsylvania and Florida.

“Campaigns tend to take an arms-race approach to advertising,” Searles said. Psychologically speaking, some campaigns believe a big number in a must-win state projects strength.

That doesn’t always work out in practice. Clinton spent $64 million on ads in Florida in 2016 — more than twice as much as Trump — and the Sunshine State still went red.