Recent ads from the animal welfare group — which are airing in the battleground state of Virginia — begin with a picture of Trump's sons, Eric Trump and Donald Trump Jr., holding up a dead leopard they shot during a hunting trip.
"A picture is worth a thousand words," the narrator says. "So, what does this one say about a Donald Trump presidency?"
The hunting habits of Trump's sons are only part of the problem, according to the group. What's more alarming, the ad says, is that the younger Trumps are gunning for seats in the presidential cabinet.
Photos of a confined hog, a shabby dog and a distressed horse appear in the same shots in the TV ad as Summit Agricultural Group CEO Bruce Rastetter, Lucas Oil CEO Forrest Lucas and Oklahoma state Sen. Eddie Fields — men Trump appointed in August to his agricultural advisory committee.
And as the ad closes, the admonishment that "a Trump presidency would be a threat to animals everywhere" is displayed next to a grid image of Trump's face, which is composed of animal photos.
The ads' sponsor
The Humane Society Legislative Fund formed in 2004 as the lobbying arm of the Humane Society of the United States, a public charity to which donations are tax-deductible.
Donations to the Humane Society Legislative Fund, however, are not tax-deductible, as it's organized as a "social welfare" nonprofit under section 501(c)(4) of the U.S. tax code.
Electoral politics cannot be the primary focus of charities or social welfare nonprofits, but thanks to the U.S. Supreme Court's Citizens United v. Federal Election Commission decision in 2010, social welfare groups are allowed to run political ads that call for the election or defeat of federal candidates.
For its part, the Humane Society Legislative Fund casts itself as nonpartisan, endorsing candidates based on their stands on animal protection issues.
This year, they're rooting for the donkey to win the White House.
"Trump represents the greatest threat ever to federal policy-making and implementation of animal protection laws, and we are taking the unusual step of wading actively into a presidential campaign," Michael Markarian, the Humane Society Legislative Fund's chief operating officer, wrote in an October blog post.
The group previously endorsed Democrat Barack Obama's presidential bid in 2008 but did not spend money on ads in prior presidential elections.
Trump himself has said little about animal welfare issues during the campaign, and he has not released a formal policy positions on such matters. But Trump this month accepted a $5,000 contribution from a political committee sponsored by the Safari Club International — the group supports big game hunting — and has periodically panned animal rights activists.
"Ringling Brothers is phasing out their elephants. I, for one, will never go again. They probably used the animal rights stuff to reduce costs," Trump wrote last year in a tweet after the circus decided to retire its performing pachyderms.
Sara Amundson, the executive director of the Humane Society Legislative Fund, said a big difference between the 2008 election and the 2016 election is money.
"We did not have the expansion of resources to engage [in 2008]," she told the Center for Public Integrity. "In this election cycle, we were very excited to be in the race."
Who's bankrolling this foray into Election 2016? It's not exactly clear.
Amundson insisted her group was "transparent," but she declined to identify any of its funders.
She simply said the majority of the Humane Society Legislative Fund's resources come from individual donors.
The Doris Day Animal League, another social welfare nonprofit that lobbies for animal protection, gave it $1.3 million that year — representing more than 30 percent of the money the Humane Society Legislative Fund received in contributions in 2014.
Tax documents also show America Votes — a group that works to help elect Democrats and bills itself as the "coordination hub of the progressive community" — donated $100,000 to the Humane Society Legislative Fund during its own 2012-2013 fiscal year.
Campaign finance records show the Humane Society Legislative Fund has spent more than $1 million on ads targeting federal races this election, including $170,000 on TV ads opposing Trump.
The animal welfare group launched its attack on Trump in early October, purchasing $10,000 worth of cable ads in Washington, D.C., that appeared on Fox, Fox News and MSNBC, said to Tim Kay, the director of political strategy at advertising firm NCC Media.
Its ads are currently airing in the Richmond, Virginia, media market, according to data provided to the Center for Public Integrity by ad tracking firm Kantar Media/CMAG. That's a state Clinton hopes to carry on Election Day, and recent polls show her with about a 3 percentage point lead over Trump.
John Cleveland, a spokesman for the Humane Society Legislative Fund, said Virginia was chosen because they thought it'd be a competitive state.
"In recent elections, polling has not been reflective of final margins, and we hoped that launching there would have the effect of shoring up support among pro-animal voters, who span both parties," he told the Center for Public Integrity. He added that the group had also purchased online advertising targeting voters in the battleground states of Florida, Nevada, North Carolina, Ohio and Pennsylvania.
The Humane Society Legislative Fund has also spent about $400,000 on ads to help elect Wisconsin Democrat Russ Feingold to the U.S. Senate again after losing his seat to Republican Ron Johnson in 2010.
Amundson told the Center for Public Integrity that any additional TV ads in 2016 would depend on an influx of money from donors.
In the meantime, it has also opted to partner with the political action committee of liberal group MoveOn.org to further promote Clinton in an online advertisement entitled "I'm With Purr."
Why it matters
Outrage over the treatment of animals has been at the forefront of the public's attention after high-profile cases involving animal deaths like Harambe the gorilla this year and Cecil the lion last year.
As president, Trump's positions on animal welfare — and his sons' trophy hunting — might not go over well with the nearly 80 million U.S. households that own pets.
On the campaign trail, Clinton herself once noted that "Trump and his kids have killed a lot of animals."
The Center for Public Integrity is a nonprofit, nonpartisan investigative news organization in Washington, D.C.