The topic of conversation of baseball fans today is last night's Detroit Tigers-Cleveland Indians baseball game. Journeyman Tigers pitcher Armando Galarraga retired the first 26 batters he faced without allowing anyone to reach base. Only twenty times in over a century of baseball history has a pitcher successfully retired every batter he faced. Galarraga was about to become the twenty-first when Jason Donald grounded to first base and was thrown out by half a step—except umpire Jim Joyce called Donald safe. Detroit's manager argued the call, but umpires rarely change their minds; indeed, it's so rare that umpires change their minds that a 1969 incident involving Cleon Jones and shoe polish is part of baseball lore. After the game, Joyce admitted he had made a mistake that cost Galarraga his perfect game.

Around the web, there are calls for Major League Baseball to retroactively award Galarraga a perfect game. A comparison is made to the "Pine Tar game" in 1983: an umpire reversed a George Brett home run for excessive pine tar on the bat, calling him out and ending the game with a New York Yankees victory over the Kansas City Royals; the American League reversed the call and ordered the last inning of the game replayed, with the Royals winning by virtue of the reinstated Brett home run.

But the difference between the Galarraga game and the Pine Tar game is material. In the Pine Tar game, the umpire made an erroneous interpretation of the rules—the penalty for using a bat with too much pine tar is to remove the bat from the game rather than to call the batter out. The Royals protested the decision under applicable baseball procedure and got the erroneous application of rules reversed. In the Galarraga game, the umpire's error is one of a bad interpretation of facts: a judgment call that is not appealable or reviewable under MLB Rule 4.19.

(Habeas aficionados will be interested to see that MLB Rule 4.19 has a "harmless error" component: even an umpire's mistaken application of the rules is not reviewable if it would not make a difference to the outcome of the game.)

There's a similar distinction in law: appellate courts will review the legal decisions of lower-court judges de novo, i.e., from scratch, but give deference to their findings of fact, reversing only when "clearly erroneous"—which can sometimes lead to controversy whether a particular finding is factual or legal in nature. Congress has passed laws relating to habeas limiting the scope of appellate decisionmaking.

There are naturally calls to change baseball rules to make more umpire judgment calls reviewable. In the National Football League, for example, teams are allowed a certain number of challenges to certain types of referee decisions, and officials review television footage of the play and can reverse the decision on the field if there is clear evidence of error. Of course, there is no such thing as a free lunch, and the increase in accuracy comes at a cost: lengthy delays as the game is stopped for game officials to peer into a television monitor and confer about what they've seen. It's not clear that baseball—whose games are already notoriously slow-paced, and getting slower by the year—can afford to add five to ten minutes a game for review calls. This is especially true because baseball's season is ten times longer than football's season, and because individual calls in a baseball game are less likely to affect the outcome of a game much less the outcome of a season. Even in the Galarraga game, the only effect of the blown call was trivia: the final score would have been 3-0 Tigers, either way. If anything, Galarraga is going to be more remembered for his 28-batter almost-perfect game than he would have been if the umpire had gotten the call right.

The same question of finality and efficiency versus accuracy arises all the time in law: in deciding whether to permit interlocutory appeals or collateral review of decisions, what level of deference to give to finders of fact in reviewing their decisions, whether to declare a mistrial, and so on. Chief Justice Roberts famously used the analogy of an umpire calling balls and strikes to the appropriate role of a judge, but the lessons of baseball can go even further.