"Baseball is the only thing besides the paper clip that hasn't changed." -- Bill Veeck

WASHINGTON -- One must say it ain't so. Think of the designated hitter, which illustrates why opposition is a sensible reflex when tinkerers propose changing baseball.

A familiar proposal is now being revived, one that involves lessons pertinent to politics, lessons about how careless advocacy can fuel the imperialism of progress. The proposal is for instant replay to assist umpires, who have recently made some bad calls on baseballs hit out of the field of play.

One was first correctly called a home run, but then was ruled a foul ball. Another was hit over the fence, but bounced back onto the field, was ruled in play, so what should have been a home run became a double, and so on.

It is not news that to err is human and so are umpires. Now, however, those ancient truths coexist with a new fact: Seemingly everything is visually recorded. After all, everyone has a camera in the phone in his or her pocket. So we can do something -- can't we? -- about imperfection. That which can be measured can be perfected, can't it? And extremism in pursuit of perfection is no vice, is it?

Because umpires' errors are displayed in television replays, perfectionists want replays available for umpires during games, at least for "boundary" calls: Was the ball that left the field fair or foul? Did a fan interfere with the outfielder?

Some problematic calls by umpires are an unintended consequence of the designs of new, fan-friendly ballparks. Some outfield fences have idiosyncratic contours, and some fences are low enough to allow outfielders to reach into the stands after balls -- and to allow fans to compete with players for possession of them.

People who oppose video replays are disparaged as baseball "purists" by disparagers who presumably are pleased to be known as "impurists." "Luddite," "antediluvians" and "mossbacks" are among the terms applied to people who say the four words that always infuriate impatient reformers: Let's think this through.

The problem is that reformers will not restrain their metabolic urge for perfection. Listen, as they seem not to, to the logic of their language. They say: If you can replay something, you can get it right -- judge it infallibly -- and that is all that matters. This is an argument for using replays on every close call -- plays at the bases and home plate, hit batters. And: Did an outfielder catch or trap a sinking line drive, etc.?

But it is not true that cameras positioned around a ballpark can answer every question, or even be more definitive than are baseball's remarkably skilled umpires who render judgments close to a play. And even if cameras could deliver certainty, it is foolish to think that all other values should be sacrificed to that one.

In the NFL, coaches' challenges, which trigger replays, contribute to the sense that a game consists of about seven minutes of action -- seriously: use a stopwatch and you will see -- encrusted with three hours of pageantry, hoopla and instant-replay litigation.

Wanting to spare baseball from promiscuous use of replays does not indicate hostility to "change." Barack Obama promises "change" as though that would be a novelty in this nation in which tumultuous change is the only constant. Even conservatives do not (quite) believe that all change, of any sort or size, at any time, for any reason, is regrettable. The problem is, progress always goes on too long, leaving us waist deep in unintended consequences. Soon we are saying "adios" to cherished familiarities. (It was a ballplayer -- Clay Carroll, a former relief pitcher for the Cincinnati Reds -- who asked, "How do you say 'adios' in Spanish?")

Baseball, like many sports, involves fast, muscular, semi-violent striving. There are inherent limits to how much precision is possible in enforcing rules. Or desirable: Human error is not a blemish to be expunged from sports, it is part of the drama.

Baseball probably will and probably should adopt replays, but only for the few "boundary" decisions. And only after considering how to make this concession to technophiles a prophylactic accommodation, one that prevents an immoderate pursuit of perfect accuracy, until the rhythm of the game is lost and the length of the game is stultifying. People impatient for replays should remember the admonition from Johnny Logan, once a Milwaukee Braves shortstop: "Rome wasn't born in a day."