Being funny isn’t “presidential.”

But once per year since 1920, presidents have cracked jokes to an audience and listened to their own roasts at the White House Correspondents’ Dinner. This year, President Obama’s speech at the dinner was laden with jokes mocking his challengers for the presidency, which enabled him to campaign by subtly trivializing issues, many espoused by major candidates, that aren’t worth more than a laugh.

The correspondents’ dinner is organized by the White House Correspondents’ Association, a body of journalists who represent the interests of the reporters and new organizations covering activities in the executive branch. The dinner is attended by employees of these news organizations, as well as by members of the executive branch, potential candidates, and party officials. Presidents attend the dinner to maintain healthy relationships with the people who report on them.

Obama used it as a stump speech, albeit a differently styled speech than the standard campaign fare.

Some issues in political discourse are so trivial that politicians don’t want to discuss them for fear of lending them credence. The old practice was to ignore these issues to avoid lending them legitimacy, but in the age of the blogosphere, 24-hour news cycles, and ideological talk-show hosts, avoiding these issues doesn’t work.

The “birther” movement was just such a topic. Since 2007, a dedicated group of individuals has challenged Obama’s citizenship with a complete lack of evidence, and avoiding the issue only made the birthers louder. The unique thing about the correspondents’ dinner is that it’s acceptable for the president to trivialize issues, which allowed him to directly address the birthers without raising their profile.

The birth-certificate issue never should have been a serious one. At the correspondents’ dinner, it was given its rightful place in the public discourse: the butt of jokes. Obama came to the podium to a montage of famous movie scenes and a large flashing copy of the president’s “long-form” birth certificate, and he made various jokes about prominent birthers and about Fox News.

Obama used the dinner as an opportunity to assault public birther Donald Trump’s legitimacy.

Trump’s face said it all. During the jokes aimed at him, he scowled, not once cracking a smile under heavy mockery. During most of the speech he delivered, Obama was smiling — but during the jokes about Trump his face was stern. Later, Obama made a joke about Michele Bachmann being born in Canada, saying, “this is how it starts, Michele.” When he delivered the lines about Trump and Bachmann, Obama seemed to have the air of a family patriarch disciplining unruly youngsters. His goal: presenting himself as the adult in the situation. And it was successful.

Later, Trump responded to the president on a phone interview with Fox, saying he felt he was targeted because he was polling so well. (A classic case of Donald Trump proclaiming victory for himself, which only works in the media game — he can’t proclaim himself the president.)

Obama’s speech at the dinner raised a point that Iowans should consider in the upcoming caucuses. Near the end of the speech, Obama made several serious remarks about soldiers fighting abroad and the victims of the natural disasters in Alabama. These remarks bring to light the fact that issues have no place in our political discourse, and in the upcoming caucuses, Iowans should keep that in mind.

Candidates will be trying to gain an edge any way they can, and the attacks on Obama will be fast and numerous. Many of them will address real flaws that the president has. Many of them will simply be hot air. Iowa voters need to differentiate between the issues that matter and baseless attacks to win political points, because fixing those problems is no laughing matter.