Donald Trump’s expected attendance at Saturday’s annual White House Correspondents’ Association dinner in Washington for his first time as president will put his administration’s often-contentious relationship with the press on full public display.

Mr. Trump will be watched closely at the event held by the organization of reporters who cover him and his administration. Past presidents who have attended have generally spoken about the importance of free speech and the First Amendment, adding in some light roasts about individual journalists.

The Republican president did not attend during his first term or the first year of his second. He came as a guest in 2011, sitting in the audience as President Barack Obama, a Democrat, made some jokes about the New York real estate developer. Mr. Trump also attended as a private citizen in 2015.

Past dinners have also featured comedians who poke at presidents. This year, the group opted to hire mentalist Oz Pearlman as the featured entertainment.

Mr. Trump’s planned appearance is rekindling a longer running debate about the dinner and events like it — in particular, whether it is poor form for journalists to be seen socializing with the people they cover. The New York Times, for example, stopped attending the dinner more than a decade ago for that reason.

“What was once (a fairly long time ago) a well-intended night of fundraising and camaraderie among professional adversaries is now simply a bad look,” wrote Kelly McBride, ethics expert at the Poynter Institute, a journalism think tank.

A contentious relationship

Between berating individual reporters, fighting organizations like the Times, The Wall Street Journal and The Associated Press in court and restricting press access to the Pentagon, the administration’s animus toward journalists has been a fixture of Mr. Trump’s second term.

On the eve of the dinner, nearly 500 retired journalists signed a petition calling on the association “to forcefully demonstrate opposition to President Trump’s efforts to trample freedom of the press.”

“The White House Correspondents’ dinner reinforces the importance of the First Amendment in our democracy,” said the WHCA president and CBS News’ senior White House correspondent Weijia Jiang. “As we mark America’s 250th birthday, our choice to gather as journalists, newsmakers and the president in the same room is a reminder of what a free press means to this country and why it must endure. Not for the media or the president, but for the people who depend on it.”

Many reporters who attend, however, consider it a valuable opportunity to get story ideas and establish personal connections with those in government, one that may pay dividends with returned telephone calls in the future.

Some news organizations invite sources as guests

Journalists often invite sources as guests at the dinner. It will be noticed Saturday whether administration officials who have also expressed hostility to the press will attend, and with whom they will be sitting.

The AP has invited Taylor Budowich, a former White House deputy chief of staff who left last fall for the private sector. The invitation is notable because Budowich, in his role crafting White House communications policy, was a named defendant last year when the AP sued the administration after it reduced its access to the president because the news outlet did not follow Mr. Trump’s lead in renaming the Gulf of Mexico.

“We maintain professional relationships with people across the political spectrum because we are nonpartisan by design — focused on reporting the facts in the public’s interest,” AP spokesman Patrick Maks said.

The White House correspondents will also hand out awards for exemplary reporting. That includes some stories that displeased Mr. Trump, such as one from the Journal about a birthday message Trump once sent to convicted sex offender Jeffrey Epstein. The story led to a presidential lawsuit.