What is an unmet promise called? Per our colloquial phrasing, a promise not kept is deemed “broken,” a subtle linguistic reminder of our reverence for the oath. That esteem for the promise exists throughout our culture. In the Bible, Moses exhorts, “When a man… binds himself under oath to a pledge, he shall not violate his word.” In the legal arena, common law long prohibited “breach of promise,” holding would-be husbands accountable for unfulfilled ring-giving (a practice that, be advised, still sits on the books in some states). And at the edge of the great abyss, Robert Frost, that great American poet, famously reminded himself, “But I have promises to keep.”

Incidentally, Vice President Joseph R. Biden Jr., partial to that ethos of promise-keeping, borrowed Robert Frost’s words for his autobiography, titled “Promises to Keep.” Support or opposition for Mr. Biden aside, that emphasis on keeping promises seems absurd when fused with the sphere of politics. Because politicians are liars. That is evident. Disenchanted voters recall a history littered with broken campaign promises. They remember the elder Bush’s infamous illiteracy with respect to his own lips. And they recall not only ignored but impossible promises too, like the 1987 vow from Bob J. L. Hawke, ex-P.M. Down Under, to end Australian child poverty by 1990. (Today, one in seven Australian children lives in poverty; Mr. Hawke has since publicly regretted the promise.) A truism: politicians break their promises.

That pattern, unlike the style of men’s basketball shorts, does not seem to have improved since the late 1980s. According to PolitiFact.com’s “Obameter,” President Barack Obama and the veracity-minded Mr. Biden have met their 506 campaign promises (yes, 506) at a paltry 31 percent clip, with a mere 6-for-25 record on “Top Promises.” Similarly, the corresponding “G.O.P Pledge-O-Meter” lists a 29 percent “Promise Kept” rate for the 2010 Republican class in Congress. Those wavering records seem logical. Politicians, for one, have an incentive to exaggerate, with the intent of wooing potential voters. And on top of that, different constituencies for primary versus general elections can encourage insouciant flip-flopping. But just how malleable, exactly, is a politician’s word?

About one-third malleable, to be precise. At least, that follows the findings of a 1985 book-length study by Jeff Fishel, professor emeritus at American University. In examining U.S. presidents from Kennedy to Reagan, Fishel found a promise-keeping rate of 66 percent, if—importantly—a stymied but real attempt to keep a promise counts as a success. (Other work has confirmed and extended this record, to 70 percent or even three-fourths.) In line with that “A for effort” approach, PolitiFact’s scores for Mr. Obama and the G.O.P. rise to 66 percent and 77 percent, respectively, when “in the works” legislation counts positively. Two-thirds is far from perfect. But, as Rutgers political scientist Gerald M. Pomper points out, compared to America’s one-in-two divorce rate, those scores are “pretty good.”

And, besides, 100 percent may be less than desirable. Mr. Bush’s lip-reading and his successor’s “most ethical administration in history” do not constitute the only reneged presidential assurances. The 1940 Roosevelt campaign promised a refrain from entry into war, a promise wisely revoked after December 7th, a year later. Lincoln promised to preserve slavery in the Southern states, and even endorsed an amendment to accomplish just that (“I have no objection to [such an amendment’s] being made express and irrevocable” —Abraham Lincoln, first inaugural address). That fell away in an 1863 proclamation. Thomas Jefferson’s Democratic-Republicans unwound their small-government, Constitutionalist promises long enough to acquire the Louisiana Territory. In 1844, James K. Polk promised a reduced tariff, a resolution of Oregon’s borders, and the annexation of California. And, well, James K. Polk actually delivered on all three. But the most famous James Polk memorial is in Pineville, North Carolina. Not Washington, D.C.

So, we have a few helpful—at least, palliative—lessons. Yes, sometimes politicians break promises. Sometimes they shatter them in a memorable, sharded frenzy. But, more often than not, they do their best—or do something, at a minimum—to follow through on those promises. Despite a world of ephemeral, present-minded concerns, of shifting, archipelagic interest-groups, and of often depthless media flaring, politicians generally stand by their word. And in times when they do not, it may even prove for the better.

The longtime politician Nikita S. Khrushchev (who, perhaps not via promise-keeping, regularly secured a 90 to 100 percent vote for his party) warned, “Politicians are the same all over. They promise to build bridges even when there are no rivers.” The latter sentence seems wittily instructive, but the first might not be true. Politicians are not “the same all over.” One glance at the 2012 field, for both parties, shows a wide gamut not just of policy options, but of personalities and of values. A glance at history yields the same. Some politicians are more malleable, more inconsistent. Some are reliable rocks. Many politicians fall somewhere in between. And some, no matter what they promise you, will still roll the Red Army into Hungary.

Brian L. Cronin ’15, a Crimson editorial writer, lives in Wigglesworth Hall.