If there's one expression that seems to have taken over the media landscape lately, it's "doubling down." Deriving from the game of blackjack, "doubling down" has taken on a figurative meaning over the past couple of decades: "to engage in risky behavior, especially when one is already in a dangerous situation," as the Oxford English Dictionary defines it. So why is everyone from Mark Zuckerberg to Bill Clinton talking about risk-taking in this way? And when is it considered a good thing?

In blackjack, "doubling down" is a move that promises a big reward, but only when the player takes a big risk. If you feel confident enough in your chances of winning after being dealt two cards, you can double your bet, but you're only allowed to take one additional card. So when "doubling down" is extended metaphorically, that high-risk, high-reward strategy can be seen as admirably bold or woefully foolhardy — or perhaps a little of both.

Let's take a look at some recent examples. Earlier this week, in his first public appearance since Facebook's notoriously rocky initial public offering, Mark Zuckerberg said that because Facebook stock is undervalued, now is "a great time for people to double down." Zuckerberg was primarily talking about retaining employees who are getting paid in stock options, but the AP wire story took that as the takeaway message, under the headline  "Zuckerberg: Time to 'Double Down' on Facebook."

Another tech company leader, Apple CEO Tim Cook, is also fond of talking about "doubling down." Back in May, at the D10 conference, Cook vowed to "double down on secrecy" to avoid product information being leaked before launch. (So much for that: this week's iPhone 5 release was thoroughly spoiled by leaks on tech blogs.) And at the same event, Cook responded to complaints about Siri, the dulcet-toned virtual assistant on the iPhone, by saying "We're doubling down on it."

Zuckerberg and Cook both used the "doubling down" expression to suggest that big bets are necessary to succeed in the tech realm, even if naysayers are aligned against you. In politics, "doubling down" can work in a similar fashion. For instance, in a speech in June, President Obama said, "Let's double down on a clean energy industry that has never been more promising." As with the techies, Obama's "doubling down" on clean energy is about being ambitious, taking bold risks, and "going all in," to use another gambling metaphor.

But if you describe your political opponent as "doubling down" on something, it's never a good thing. In his speech at the Democratic National Convention, Bill Clinton used it against Mitt Romney in a clever turn of phrase: "We simply cannot afford to give the reins of government to someone who will double down on trickle-down." Later he continued the gambling theme: "So far, every single person that’s bet against America has lost money because we always come back." (See last week's Word Routes, "Fixin' to Get Folksy," for more on the rhetoric of Clinton's speech.)

Reporters enjoy using the "doubling down" metaphor when a politician sticks to his or her guns in a dicey situation. Often it implies a kind of intransigence, perservering with a seemingly poor decision and amping it up rather than backing off. For example, when Romney kept up his criticism of what he saw as the Obama adminstration's "apologetic" response to the embassy attacks in Egypt and Libya this week, numerous news reports described this as "doubling down" on his initial rebuke.

It's safe to say that "doubling down" has reached cliché status, if grumbling about its overuse is any indication. In June, when CBS News ran an online headline "GOP doubles down on health care repeal promise," one commenter vented: "The term 'double down' seems to be used a lot by the media. Are they implying that the whole U.S. economy is one big blackjack table in the casino of life? Please find a better term to use rather than falling back on the easy and sloppy cliches." On Twitter, there have been many appeals for journalists to stop using the expression.

So why is "double down" the alliterative phrase du jour? Let's not blame KFC and their outrageously unhealthy Double Down sandwich from a couple years back. (For people unfamiliar with blackjack, though, this misbegotten concoction, involving bacon and cheese sandwiched between two chicken filets, may be their primary association for the phrase.)

I see it as part of our growing penchant for using the language of gambling in other spheres of life, especially when it involves making "bets" and seeking "payoffs" in politics and business. I talked about this linguistic trend on the public radio show "Marketplace" in July, after Obama kicked off a campaign tour that he called "Betting on America." As I said at the time, the metaphor of betting is a double-edged sword: it may summon all-American images of audacious risk-taking on the frontier, but when we're living in risk-averse times such figures of speech might not be so pleasing. "Doubling down" cuts both ways, but whether the expression is used to describe a smart bet or a foolish one, it's time to give it a rest.

You can listen to my "Marketplace" interview about the language of gambling in politics here. And check out Mark Liberman's response on Language Log for more historical context.