He may or may not be the next Bill Klem, but at least John Roberts is no Janice Rogers Brown.

OK, these names are not household words, save perhaps in selected households of the political left, the political right, and the baseball-obsessed. So let’s explain.

William J. Klem was the first of the great umpires, the original "Old Arbitrator," umpiring in 18 World Series in a career that stretched from 1905 to 1941.

John Roberts is not an umpire. He is the new chief justice of the United States. Nonetheless, he told the Senate Judiciary Committee — before it, and subsequently the full Senate, approved his nomination — that "judges are like umpires. Umpires don’t make the rules; they apply them … I will remember that it’s my job to call balls and strikes and not to pitch or bat."

Janice Rogers Brown is not an umpire, either. She is a judge on the District of Columbia Circuit Court — and someone whom President Bush could have nominated in Roberts’ stead. Judge Brown would be far less likely than Roberts to use the umpire image. Temperamentally, she’s more the revolutionary, or rather the counter-revolutionary, against what she has called "the revolution of 1937," the year of "the triumph of our own socialist revolution."

The notion that we ever had a triumphant socialist revolution might appear bizarre to many observers. But Judge Brown is only one of the lawyers, economists, and right-wing think-tank policy mavens who contend that there is a "hidden Constitution" or "Constitution in exile" that was supplanted in 1937 when the Supreme Court upheld both the Social Security and the Wagner (National Labor Relations) Acts.

According to the counter-revolutionaries, these decisions were based on an invalid reading of the constitutional clause giving Congress the power to "regulate commerce … among the several states." The Founders, they argue, only meant to make the nation one free-trade zone, not to permit Congress to regulate private economic activity.

The substantive result of a narrow interpretation of the Commerce Clause would be to weaken, if not abolish, federal laws that protect consumers, workers, minorities and the environment. Those laws are based on Congress’ power to regulate interstate commerce.

But Judge Roberts, based on his testimony to the Judiciary Committee, is no counter-revolutionary. He regularly extolled the virtues of judicial restraint and judicial precedent. He all but disdained the "originalist" outlook associated with the "hidden Constitution" viewpoint. And when asked about the Commerce Clause, he rejected all opportunities to suggest that he would narrow its interpretation.

Though there were several such questions, the one most pertinent to this discussion came from Sen. Charles Schumer, D-N.Y.: "Let me ask you, then, this hypothetical (question): (Suppose) it came to our attention (that) individuals were now able to clone certain species of animals, maybe an arroyo toad (which) didn’t pass over state lines. … Under the commerce clause, can Congress pass a law banning (such) cloning?"

"It would seem to me," Roberts said, "that Congress can make a determination that this is an activity … that is going to have effects on interstate commerce."

That was a yes.

Schumer did not specify the arroyo toad out of some playful puckishness, a trait with which he is not generally associated. That species was the subject of a case in which then-Appeals Court Judge Roberts, dissenting, opined that Congress could not protect the toad under the Endangered Species Act because "for reasons of its own (it) lives its entire life in California."

The new chief justice’s history and testimony leave little doubt that Roberts is a conservative, possibly inclined to look for reasons to support commercial interests. If the developer on the mound throws one just above the letter of the environmental law, Roberts seems more likely to call it a strike than would, say, Justices Ruth Bader Ginsberg or David Souter.

But chin-high? Probably not. Unlike the counter-revolutionaries, Roberts appears to be capable of being embarrassed — a desirable characteristic in both the folks in black robes and the men in blue.

What about Harriet Miers, President Bush’s choice to replace Justice Sandra Day O’Connor? Her strike zone remains a complete mystery, and not just because she has not yet appeared before the Judiciary Committee. She simply has never held a position in which her constitutional views were relevant.

Miers, one might say, is this administration’s Joey Cora. Cora is not an umpire. He’s the third-base coach of the Chicago White Sox, the new champions of the American League.

Miers is the White House counsel. Like third-base coaches, White House counsels are (a) technicians rather than policy-makers (relaying the "bunt’’ sign from the manager; checking the legality of a proposal); (b) largely unknown unless they mess up (waving home a runner who gets thrown out; apparently acquiescing to the torture of prisoners); (c) employed because they toady to the guy who appoints them (the manager; the president).

Like Roberts, Miers is conservative. Is she also — like Janice Rogers Brown — a counter-revolutionary? There is, as of yet, no way to tell.

Jon Margolis writes about the doings in Washington, D.C., from a safe distance — Vermont.