Democratic presidential candidates will enjoy some free face time Tuesday in Las Vegas for their first nationally televised debate, but tenuous frontrunner Hillary Clinton has already spent considerable time on the airwaves, thanks to her prodigious advertising budget.

The Clinton campaign has bought and aired nearly 5,500 TV ads this year through Monday targeting voters in the early presidential caucus and primary states of Iowa and New Hampshire, according to a Center for Public Integrity analysis of data from Kantar Media/CMAG, an advertising tracking firm.

Such a number accounts for nearly one in four TV ads aired so far during the 2016 presidential race by any source, Democrat or Republican.

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That includes any of nearly two-dozen other presidential candidates, political parties and political action committees. It also includes big-dollar super PACs and nonprofit groups, which thanks to the Supreme Court’s 2010 Citizens United v. Federal Election Commission decision may raise and spend unlimited amounts of money to advocate for political candidates.

Measured another way: Clinton’s campaign has aired more TV ads than the campaigns of Republicans Donald Trump, Jeb Bush, Ben Carson, Ted Cruz, Rand Paul and Marco Rubio — combined.

Consider that Sen. Bernie Sanders of Vermont — so far Clinton’s main Democratic primary rival who has of late risen in polls, especially in New Hampshire — has yet to air a single TV ad while drawing huge crowds to campaign events.

Nor have the campaigns of Clinton’s other Democratic challengers who will debate her on Tuesday: former Rhode Island Gov. Lincoln Chafee, former Maryland Gov. Martin O’Malley and former Sen. Jim Webb of Virginia — although a super PAC backing O’Malley, called Generation Forward PAC, has aired a few dozen ads in Iowa.

Clinton certainly doesn’t need TV ads to help in the name recognition department: A Gallup poll this summer concluded, unsurprisingly, that Democratic voters are almost universally familiar with her. On the Republican side, only Donald Trump challenges the Clinton name’s ubiquity.

Clinton’s problem? Many people just don’t like her. Gallup in September placed her overall favorability rating at 41 — the lowest it’s been since the early 1990s, when she had just moved into the White House as first lady.

A number of factors explain why.

Clinton has endured massive fallout from her use of a private email server as secretary of state. She’s faced lingering questions about her actions before and after the killing of Amb. Christopher Stevens and three associates in Benghazi, Libya. She’s gone weeks at a time without conducting unscripted interviews, feeding concerns that she’s unshakably secretive.

Her campaign has also at times appeared ham-handed: It paradoxically revealed, for example, that Clinton was planning to become more spontaneous — earning her more than a few snickers and barbs.

Each Clinton TV spot until this week largely focused on Clinton herself, generally casting the former U.S. senator and secretary as decisive and visionary, Kantar Media/CMAG data indicates.

Many ads tout her work on health care matters, student debt, equal pay and other perceived concerns of people Clinton has called “everyday Americans.”

One ad features her new granddaughter.

“You should not have to be the grandchild of a former president to know you can make it in America,” Clinton says in the spot as upbeat music plays. “That will be my mission as president: to make sure I do everything I can, every single day, to knock down the barriers, to open up the doors, so that every child has a chance to live up to his or her God-given potential.”

Save for a few vague swipes at unnamed Republicans, not one Clinton-sponsored ad through Monday pilloried Sanders, or chided Trump, or contrasted Clinton’s political or governmental records with those of Republican candidates such Bush or Sen. Marco Rubio.

There’s some evidence Clinton’s Hillary-first advertising strategy has helped her earn prospective voters’ admiration as she attempts to re- re- re- reintroduce herself to a body politic already well-acquainted with her decades-long political career.

While Clinton’s net favorability rating among Democrats declined throughout August and much of September, it’s ticked upward of late and most recently stands at 53 percent.

“She’s the least-known best-known figure in America, and she’s trying to stop the bleeding at this point,” said John Carroll, a Boston University mass media professor who specializes in political messaging. “She’s also trying to prove to the public that she’s not a hologram, that she has dimension.”

The Clinton campaign did not respond to requests for comment.

Clinton hasn’t completely received a free pass when it comes to opponents’ paid media, and her road ahead is about to become more crowded.

Democratic presidential candidate Larry Lessig, a Harvard University professor who’s largely running on one issue — campaign reform — went up this week with a TV ad that attacks not Clinton or Sanders, but Rubio. It doesn’t appear Lessig, who entered the presidential race last month, will qualify for Tuesday’s Democratic debate.

Meanwhile, a political committee urging Vice President Joe Biden to run for the Democratic nomination has also invested six-figure amounts this month into TV ads.

Generation Forward PAC, the pro-O’Malley super PAC, has spent about $156,000 TV ads, digital ads, mailers, T-shirts and other messages designed to boost O’Malley, according to its filings with the Federal Election Commission. Additionally, the Baltimore Sun reports it will be spending $215,000 on a new ad buy.

Republican groups have spent about $2 million to date on non-TV messages opposing Clinton, such as digital ads and emails, according to the Sunlight Foundation.

Going forward, expect Clinton to smack back. She this week aired an ad that attacked a Republican by name. House Majority Leader Kevin McCarthy, who tied a Republican-led committee investigating Clinton’s actions in the Benghazi massacre to her declining poll numbers.

The timing for Clinton was prime, if coincidental, as McCarthy’s bid to become the next speaker of the U.S. House crumbled Thursday in dramatic fashion.

Clinton’s campaign had raised about $48 million as of June 30, while Sanders’ campaign had collected about $15 million. Both Clinton and Sanders pulled in about $25 million between July and September, their campaigns have announced.

Official campaign finance filings for all candidates must be submitted to the FEC on Thursday, two days after the Democratic debate.

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