Modern politicians are some of the most hated individuals in our country today. Every two years, their records — which are, in many cases, decades old — are trotted out and inconsistencies — sometimes decades apart — are revealed. And the frustration with their alleged flip-flopping only is used as a heavy weapon against their candidacy for reelection.

But why should we care about such inconsistencies? It is emphatically the role of politicians, as guardians of the public realm, to adapt to changing circumstances in the world. To the extent that they do so, they are successful. When they dogmatically uphold ideology, they become immovable, unadaptable and are open to attack and destruction from every direction.

In following their party lines — whether of formal parties or of strict adherence to their voter base’s ideology — they become like a strong bridge in an earthquake zone. It is the bridges that are constructed with a certain amount of slack and variability that survive otherwise catastrophic earthquakes. And it is the immovable, unshakable ones that collapse into the sea.

I recently read an article from 1977 by the political scientist Henry Fairlie. In it, he discusses the need for politicians to be capable of adapting to changing circumstances. And the facts of the world change all the time, especially in such a small, globalized world as our own. Politicians must contend, Fairlie writes, with all the world’s imponderabilia — all its unpredictability. Politicians must act and react in response to surrounding events. No event occurs in a vacuum. No event occurs in isolation. No event is protected from unintended, unforeseen consequences.

Fairlie writes: “[T]he art of making a majority…is the essential work of a politician in any circumstances in any country, yet it is exactly at this point that all the popular prejudices against him come into play, as he is criticized for maneuvering, for wheeling and dealing, for compromising.” The practice of politics necessarily destroys ideological commitments. Political action is negotiation: It is a back-and-forth activity, a give-and-take process which seeks to craft a solution to the problems of the day. Politics is negotiation.

A politician’s “coalitions … will be of the moment, for the moment, a succession of alliances whose composition will vary from occasion to occasion, and issue to issue.” And that is a matter of course. Not every politician will have the same views on every subject, or even on any subject. To the extent that politicians agree with one another without having discussed an issue, they have not practiced politics — they have not acted as politicians.

The politicians who adhere to ideological purity “act in isolation, and therefore are not as effective as they might be.” Insistence on purity leads to politics being done by force of numbers. Now, I realize that American politics and the military exploits of Napoleon are significantly dissimilar, but it is important to remember that Napoleon’s genius was obscured by his later victories. Toward the end of his career, his battles were fought — and often won — with reliance on sheer force of numbers. It was the weight of hundreds of thousands of French muskets and bayonets, not their maneuvering, that carried the day.

But early in his career, Napoleon’s victories were stunning. Why? Because they were carried out by clever maneuvers, as in a game of chess. Austerlitz was a masterpiece; but Borodino was a bloody, inconclusive mess that drained away precious resources in a Pyrrhic fashion. And politics should be conducted in the same way as warfare. Care should be taken to ensure that space for maneuver is preserved, that space to act correctly remains.

True, wise men build their houses upon rocks, but houses aren’t exposed to constant change. They have no need of adapting to the changing actions of their surroundings. Unless, that is, they live in an earthquake zone.