In the wake of a Washington Post story about the strategic calculations being made inside the campaign of former Massachusetts governor Mitt Romney about how best to attack the rapidly rising candidacy of Newt Gingrich , the former House Speaker has issued an edict: Play nice.

Republican presidential candidate, former House Speaker Newt Gingrich makes his way to the podium during a meeting with employees at Nationwide Insurance, Thursday, Dec. 1, 2011, in Des Moines, Iowa. (AP Photo/Charlie Neibergall)

Gingrich’s “kill Mitt with kindness” strategy sounds good. But, in practice, it won’t likely work. And Gingrich’s campaign shouldn’t stick to it if they want to win.

Campaigns are about choices. And it’s impossible for voters to make that sort of choice without knowing where the candidates differ — particularly in a Republican primary where the candidates tend to be similar on most issues and where voting decisions are more ideologically motivated.

The way those differences are typically drawn is via negative, er, comparative ads. While voters always say that they deplore negative ads, candidates (and the people who make a living making ads) continue to produce them in race after race, election after election.

Why? Because they work.

And you can bet that Romney and his campaign team will have little hesi­ta­tion in running an avalanche of ads that cast Gingrich as the ultimate political insider who has taken a variety of contradictory positions on issues of major import to Republican voters if they deem it necessary to making the former Massachusetts governor the nominee.

Since he lost almost every member of his senior leadership team in a June staff exodus, Gingrich has pledged to run a campaign the likes of which no one in the political world had ever seen before. (He also compared himself to Wal-Mart founder Sam Walton and McDonald’s founder Ray Kroc in the new Politico e-book titled “The Right Fights Back”.) Gingrich’s insistence that neither he nor anyone in his campaign will attack Romney is likely part and parcel of that pledge.

But, it’s an indisputable fact in politics that unilateral disarmament doesn’t work. A negative ad unanswered is a negative attack believed (by voters).

(Remember how long Massachusetts Sen. John Kerry waited to respond to the attacks by the “Swift Boat Veterans for Truth” during the 2004 presidential campaign? And we know how that one turned out.)

Gingrich didn’t become Speaker of the House in the 1990s or re-claim his 2012 presidential bid from the verge of political destruction by charging at windmills. He may be a man of ideas but there is a pragmatic core to him as well that has kept him relevant in national politics for nearly three decades.

And so, while his current insistence of playing nice with Romney is a nice talking point, it’s virtually impossible to see Gingrich sticking to that pledge if he actually wants to win the Republican presidential nomination.