After delivering a statement on the U.S. military campaign against the Islamic State, President Obama took two questions Monday from the press corps at the Pentagon. Asked whether he would boost the size of the U.S. force fighting the militants in Iraq to more than 3,000, he relied on an old comparison.

“The strong consensus is… we have to develop local security forces that can sustain progress,” Obama said. “If we try to do everything ourselves all across the Middle East and all across North Africa, we’ll be playing Whac-a-Mole.”

At that point, Obama left the podium.

“I didn’t even plan to do this,” he said. “You got to have two bonus questions!”

Twitter lit up. Mark Knoller, a veteran CBS News White House correspondent, offered the following:

J.M. Berger, a national security analyst and co-author of the book “ISIS: State of Terror,” added this:

Things progressed from there:

As Berger noted, comparisons between national security problems and the varmint-bonking arcade game go back a long way. Spelled either by its trademarked name or as Whack-a-Mole, it has been used by generals, politicians, pundits and rank-and-file troops alike.

Wirth, an undersecretary of the State Department in the Clinton administration, made the comparison during a House Foreign Affairs subcommittee meeting on terrorism efforts. It actually drew laughs at the time.

The hearing, archived by C-SPAN here, covered the first bombing of the World Trade Center by al-Qaeda, an alleged 1993 assassination plot on the life of former President George H.W. Bush and the 1988 bombing of Pan Am Flight 103 as it was flying from London to New York, among other threats.

“It’s a little bit like Whac-a-Mole,” Wirth said in response to a question on the range of terrorist threats. “Have you ever been to an amusement park and seen that game Whac-a-Mole? You put in a quarter and you get so much time and you’re whacking down as things pop up. You’re whacking over here and they pop up over here.

“And we have to continue to play Whac-a-Mole on this, and there are these new phenomenon that are coming up, and your question points out that we need to be more adaptable and increasingly vigilant and increasingly well coordinated in taking this on.”

Interestingly, the debate has evolved. While Wirth said the U.S. government had to play Whac-a-Mole with terrorist threats, comparisons to the game are more apt now to describe an exercise in futility.

“Now the fight against the Islamic State has introduced a new concept into modern warfare,” Washington Post columnist Dana Milbank wrote in a piece this morning in response to Obama’s remarks. “Call it Operation Whack-a-Mole.”

“The tactical, whack-a-mole approach is not having the desired effect,” Micah Zenko, a counterterrorism analyst at the Council on Foreign Relations, told the New York Times last month.

“Expanding to a full-court game of global, military whack-a-mole against a presumed global adversary in the Islamic State poses, for the United States, potentially serious costs, risks, and long-term consequences, especially those of the unintended variety,” national security analysts Gordon Adams and Richard Sokolsky wrote in a column for Foreign Policy magazine in May.

During the Iraq War, the phrase was used as concerns were raised about the difficulties in stopping sectarian violence.

“What I worry about is we’re playing a game of Whac-a-Mole here,” Sen. John McCain (R.-Ariz.) told Army Gen. John Abizaid, then the chief of U.S. Central Command, during a 2006 congressional hearing. “We move troops… it flares up…. we move troops there. We all know that Fallujah was allowed to become a base of operations of the insurgency, so we had to go into Fallujah and fight one of the great battles of Marine Corps and Army history.”

In 2008, Gen. James T. Conway, then the top officer in the Marine Corps, raised similar concerns about fighting militants, and said they would move to new parts of the globe when squeezed.

“These people will play a whack-a-mole game with us,” Conway told the San Diego Union-Tribune. “Where we squeeze them, they will go someplace else and then we will have to go there. Other nations will have to help us defeat the enemy and discourage their people from accepting the philosophy of extremism.”

Former Defense Secretary Robert M. Gates, among others, raised similar concerns about how to prosecute the Afghanistan War.

“Well, that’s one of the problems with a pure counterterrorism strategy, is that that really is Whack-A-Mole,” Gates told reporters at the Pentagon in 2010, advocating a nuanced effort to countering the Taliban. “And the virtue of the approach that we’re taking and of the strategy that the president approved was that his approach was, we’re not going to clear and attempt to hold areas that we can’t — that we don’t think we can transfer to the Afghans.”

Gen. David Petraeus used the term in his 2011 Senate confirmation hearing, when he was up to become director of the CIA.

“We can’t get into a game of Whack-A-Mole. We have to whack all the moles simultaneously,” he said.

A footnote on Whac-a-Mole: The inventor of the game, Aaron Fechter, dealt with an unexpected explosion in his own warehouse in 2013. After creating his famous game and animatronic rock bands for the restaurant Chuck E. Cheese, he set his sights on developing a new cooking fuel that burned cleaner than propane. Turns out, it was volatile, too. No one was injured, but it left pieces of armor, arcade games and clown suits littering the street after the explosion, according to the Orlando Sentinel.