LOS ANGELES >> The federal act that created public broadcasting is marking its 50th year, but if President Donald Trump has his way it will be its last with government funding.

Trump’s 2018 budget proposal makes him the second president to try to kill funding for the Corporation for Public Broadcasting (CPB) and the first to target the National Endowment for the Arts and the National Endowment for the Humanities as well.

The White House plan released Thursday, which emphasizes military and other security-related spending and slashes many domestic programs, is the first step in a lengthy budget process that ultimately requires Congressional approval.

The three agencies combined receive about $740 million annually in tax dollars. It’s a sliver of the current $4 trillion federal budget but carries outsized importance in political symbolism and, both supporters and detractors say, economic impact.

Reaction was swift from the agencies and the art and entertainment world. Alarm was the common thread.

“We’re celebrating the 50th anniversary of the Public Broadcasting Act, what I think has been the most successful public-private partnership — how ironic it would be if we were defunded this year,” said Paula Kerger, chief executive for PBS. The nonprofit group’s yearly CPB grant pays for programs that are distributed to member stations.

The proposal is “counter to the message that American art can reflect society, it can advance society, it can inspire society,” said Gina Prince-Bythewood, director of movies including “Beyond the Lights” and co-creator of Fox TV’s new drama, “Shots Fired.”

“It’s horrifying to think that can go away, and I have to stay optimistic and believe that (the cuts) won’t go through,” she said.

Kate Shindle, president of the 51,000-strong Actors’ Equity Association that represents stage actors and stage managers, said the NEA’s $148 million reaps a “return on investment” for both the culture and the economy.

“The arts are not a frill, a luxury, or some kind of extended vanity project,” she said. “The arts are a part of who we are as a nation, and the arts put our nation to work. Millions of people have jobs based on spinoff effects in hotels, restaurants, retail stores, and other business that benefit from spending on the arts.”

William D. Adams, chairman of the NEH, said the agency was “saddened” by Trump’s move and noted the agency’s five-decade funding of books, film, museum exhibits and other projects that have “inspired and supported what is best for America.”

Trump’s budget plan makes no specific argument for eliminating the agencies, although the proposal follows a paragraph describing the intent to “redefine the proper role” of the federal government.

But the conservative Heritage Foundation has been a vocal advocate of such cuts for decades and is again in its “A Blueprint for Balance: A Federal Budget for 2017.” Paul Winfree, who was lead editor on the document, has since joined the White House as director of budget policy.

“We fundamentally believe the arts are able to flourish independently of the federal government,” said Romina Boccia, the foundation’s deputy director.

Among the problems she says federal funding can create: A distortion of the art market as private funding migrates to projects seen as having the “federal stamp of approval,” and “cultural cronyism.”

Such cronyism, she alleges, can be seen in the NEA’s distribution of grants to regional arts projects in every state.

“Not necessarily because it creates the best art but because they (the NEA) are trying to secure political support so they can continue to exist,” Boccia said.

But it’s public broadcasting that’s been the recurring target for conservative lawmakers.

Many Republicans vowed to eliminate its subsidies in 1995, but the effort fizzled. In 2005, Republicans controlling the House tried to cut subsidies for PBS, National Public Radio and hundreds of public radio and TV stations by $100 million, igniting an outcry from fans of “Sesame Street” and other defenders of public broadcasting.

That bid failed. So did President George W. Bush’s repeated tries to eliminate CPB funding altogether — but not for the NEA or NEH — despite a GOP-controlled Congress in some years of his White House tenure.

The federal subsidy of $445 million to CPB represents, on average, 15 percent of public TV and stations’ funding overall, at a cost of $1.35 per person yearly, PBS said. The rest comes from private and corporate donors.

But some stations rely more heavily on public dollars, with a number of those located in areas that voted for Trump.

Among them are KTOO TV and its sister public radio stations in Juneau, Alaska. Federal dollars make up $1.3 million of its $3.2 million budget, spent on programming including Alaska-wide broadcasts of the state legislature sessions held in the hard-to-reach capital city.

Trump’s proposal “would be absolutely devastating for my station and for all of the stations in Alaska,” said Bill Legere, KTOO general manager.

As in the past, Kerger said, informing legislators about what PBS does and mustering citizen support for public broadcasting is key. One new step this year: PBS commissioned an independent poll to measure that backing and circulated the results widely, including among lawmakers and online.

“It found what we’ve always said: We have very strong support from Democrats, Republicans and independents across the country,” Kerger said.

PBS, an independent organization, and its member stations are free to lobby lawmakers. The NEA and NEH face restrictions as federal agencies and have to rely on the kindness of strangers to defend them.

While the NEA can’t engage in advocacy “we will, however, continue our practice of educating about the NEA’s vital role in serving our nation’s communities,” Jane Chu, the agency’s chairman, said in a statement.

Whether the GOP’s hold on both the White House and Congress makes Trump’s proposed cuts a reality is something that neither observers nor stakeholders are able to say.

“In a Reagan or Bush era, it would have been almost impossible for Republicans to do this, because their donors wouldn’t have allowed it,” said Dan Schnur, who teaches political communications at the Annenberg School for Communications at the University of Southern California.

But times may have changed.

“It is a different Republican party in 2017 and that makes an approach that used to be impossible not just fairly improbable,” Schnur said.

PBS’ Kerger said that she takes “nothing for granted.”

“It’s very important if people care about issues that they weigh in,” she said.