Public service is supposed to be open to everyone, but our politicians and cultural elites have turned it into something only liberals want to do.

Take the most recent crop of Truman Scholars, a federal grant program that honors the former president. The prestigious scholarship gives college juniors $30,000 toward grad school provided they serve three of their first seven years after they get out in public service — and the winners seem to be overwhelmingly liberal.

According to recent data compiled by the College Fix, “More than 40 of the 112 scholars in 2015 and 2016 have ties to Democratic politicians or liberal groups while less than a handful were found to have worked for Republicans or conservative organizations.”

Many, according to their résumés, worked for President Barack Obama’s 2012 campaign or Hillary Clinton’s in 2016 or for Planned Parenthood, the NAACP, the Feminist Majority, etc. In 2015, only two scholars listed conservative employers (the American Enterprise Institute and Americans for Prosperity).

Part of the skew may be the rule that colleges, now dominated by the left, recommend students for this honor.

But the “public service” rule surely plays a role, too, since the phrase these days is usually code for liberal activism. Indeed, at his first public appearance since leaving office, Obama reminisced about his life as a “community organizer,” then told University of Chicago students that he’s devoting his life now to getting more young people involved in public service.

Turns out, treating public service as a liberal thing is actually US government policy. The Federal Public Service Loan Forgiveness program lets you escape your student loans if you work for a government agency or a nonprofit for 10 years after college. A Brookings Institution report last year noted that up to a quarter of the US workforce qualifies.

Not only do we forgive the loans of people working at think tanks and lobbying groups and your local DMV; the program also covers a lot of other professionals — a journalist working for NPR, a doctor working at a nonprofit hospital, a university administrator.

Public service used to entail some kind of sacrifice. What are these people giving up? Surely we should have some way of distinguishing between people who pass up white-shoe law firms to become public defenders and your typical government bureaucrat.

Indeed, it seems just about everyone is engaged in public service now. With one big exception: businessmen and -women. The message is that if you work for an organization that makes a profit, you’re not contributing to the public good.

And that is where the political bias of the term “public service” becomes evident. Many conservative students are happy to serve their country — in the armed services, running for office, teaching underprivileged kids — but they’re just as inclined to believe that communities benefit from well-run businesses. Harry Truman himself owned a small business before he went into politics.

So before we offer one more program or hear one more speech encouraging public service, maybe we could acknowledge that our cities and towns could get more out of an influx of hardware stores, restaurants, banks, car dealerships, etc. than they could from a gaggle of paid community organizers.

Naomi Schaefer Riley is a senior fellow at the Independent Women’s Forum.